645291992 has 32 divisors (see below), whose sum is σ = 1257260400. Its totient is φ = 310122624.

The previous prime is 645291991. The next prime is 645292019. The reversal of 645291992 is 299192546.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645291991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46538 + ... + 58790.

Almost surely, 2^645291992 is an apocalyptic number.

It is an amenable number.

645291992 is a deficient number, since it is larger than the sum of its proper divisors (611968408).

645291992 is a wasteful number, since it uses less digits than its factorization.

645291992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12515 (or 12511 counting only the distinct ones).

The product of its digits is 349920, while the sum is 47.

The square root of 645291992 is about 25402.5981348365. The cubic root of 645291992 is about 864.1426197750.

The spelling of 645291992 in words is "six hundred forty-five million, two hundred ninety-one thousand, nine hundred ninety-two".