402578640 has 80 divisors (see below), whose sum is σ = 1386667200. Its totient is φ = 107353728.

The previous prime is 402578639. The next prime is 402578663. The reversal of 402578640 is 46875204.

402578640 is a `hidden beast` number, since 4 + 0 + 2 + 5 + 7 + 8 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×402578640² = 324139122768499200, 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 = 402578595 and 402578604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91030 + ... + 95349.

It is an arithmetic number, because the mean of its divisors is an integer number (17333340).

Almost surely, 2^402578640 is an apocalyptic number.

402578640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

402578640 is an abundant number, since it is smaller than the sum of its proper divisors (984088560).

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

402578640 is a wasteful number, since it uses less digits than its factorization.

402578640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186401 (or 186389 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 402578640 is about 20064.3624369178. The cubic root of 402578640 is about 738.3862080610.

The spelling of 402578640 in words is "four hundred two million, five hundred seventy-eight thousand, six hundred forty".