645102404 has 6 divisors (see below), whose sum is σ = 1128929214. Its totient is φ = 322551200.

The previous prime is 645102397. The next prime is 645102407. The reversal of 645102404 is 404201546.

It can be written as a sum of positive squares in only one way, i.e., 374499904 + 270602500 = 19352^2 + 16450^2 .

It is a super-2 number, since 2×645102404² = 832314223293158432, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645102407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80637797 + ... + 80637804.

It is an arithmetic number, because the mean of its divisors is an integer number (188154869).

Almost surely, 2^645102404 is an apocalyptic number.

It is an amenable number.

645102404 is a deficient number, since it is larger than the sum of its proper divisors (483826810).

645102404 is a wasteful number, since it uses less digits than its factorization.

645102404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161275605 (or 161275603 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 645102404 is about 25398.8661951671. The cubic root of 645102404 is about 864.0579825771.

The spelling of 645102404 in words is "six hundred forty-five million, one hundred two thousand, four hundred four".