1556144640 has 480 divisors, whose sum is σ = 5946248880. Its totient is φ = 374341632.

The previous prime is 1556144633. The next prime is 1556144641. The reversal of 1556144640 is 464416551.

1556144640 is a `hidden beast` number, since 1 + 5 + 5 + 6 + 1 + 4 + 4 + 640 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 982446336 + 573698304 = 31344^2 + 23952^2 .

It is a tau number, because it is divible by the number of its divisors (480).

It is a super-2 number, since 2×1556144640² = 4843172281201459200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1556144595 and 1556144604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1556144641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11358652 + ... + 11358788.

Almost surely, 2^1556144640 is an apocalyptic number.

1556144640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1556144640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2973124440).

1556144640 is an abundant number, since it is smaller than the sum of its proper divisors (4390104240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1556144640 is a wasteful number, since it uses less digits than its factorization.

1556144640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 193 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 1556144640 is about 39447.9991888055. Note that the first 3 decimals coincide. The cubic root of 1556144640 is about 1158.8217922095.

The spelling of 1556144640 in words is "one billion, five hundred fifty-six million, one hundred forty-four thousand, six hundred forty".