645242920 has 64 divisors (see below), whose sum is σ = 1731352320. Its totient is φ = 211605504.

The previous prime is 645242903. The next prime is 645242921. The reversal of 645242920 is 29242546.

It is not an unprimeable number, because it can be changed into a prime (645242921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43657 + ... + 56536.

It is an arithmetic number, because the mean of its divisors is an integer number (27052380).

Almost surely, 2^645242920 is an apocalyptic number.

It is an amenable number.

645242920 is an abundant number, since it is smaller than the sum of its proper divisors (1086109400).

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

645242920 is a wasteful number, since it uses less digits than its factorization.

645242920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100234 (or 100230 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 645242920 is about 25401.6322310201. The cubic root of 645242920 is about 864.1207143007.

The spelling of 645242920 in words is "six hundred forty-five million, two hundred forty-two thousand, nine hundred twenty".