1643750640 has 120 divisors (see below), whose sum is σ = 6308890848. Its totient is φ = 375713280.

The previous prime is 1643750623. The next prime is 1643750657. The reversal of 1643750640 is 460573461.

It is a happy number.

1643750640 is a `hidden beast` number, since 1 + 6 + 4 + 3 + 7 + 5 + 0 + 640 = 666.

1643750640 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (1643750623) and next prime (1643750657).

It is a tau number, because it is divible by the number of its divisors (120).

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 = 1643750595 and 1643750604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 158031 + ... + 168110.

Almost surely, 2^1643750640 is an apocalyptic number.

1643750640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643750640 is an abundant number, since it is smaller than the sum of its proper divisors (4665140208).

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

1643750640 is a wasteful number, since it uses less digits than its factorization.

1643750640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326167 (or 326158 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 1643750640 is about 40543.1947433845. The cubic root of 1643750640 is about 1180.1720136098.

The spelling of 1643750640 in words is "one billion, six hundred forty-three million, seven hundred fifty thousand, six hundred forty".