1555491840 has 704 divisors, whose sum is σ = 6451881984. Its totient is φ = 311427072.

The previous prime is 1555491827. The next prime is 1555491841. The reversal of 1555491840 is 481945551.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 1555491792 and 1555491801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1555491841) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42040302 + ... + 42040338.

Almost surely, 2^1555491840 is an apocalyptic number.

1555491840 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 1555491840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3225940992).

1555491840 is an abundant number, since it is smaller than the sum of its proper divisors (4896390144).

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

1555491840 is a wasteful number, since it uses less digits than its factorization.

1555491840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 42.

The square root of 1555491840 is about 39439.7241369663. The cubic root of 1555491840 is about 1158.6597282960.

The spelling of 1555491840 in words is "one billion, five hundred fifty-five million, four hundred ninety-one thousand, eight hundred forty".