645405996 has 12 divisors (see below), whose sum is σ = 1505947352. Its totient is φ = 215135328.

The previous prime is 645405989. The next prime is 645405997. The reversal of 645405996 is 699504546.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (645405997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26891905 + ... + 26891928.

Almost surely, 2^645405996 is an apocalyptic number.

It is an amenable number.

645405996 is an abundant number, since it is smaller than the sum of its proper divisors (860541356).

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

645405996 is a wasteful number, since it uses less digits than its factorization.

645405996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53783840 (or 53783838 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 48.

The square root of 645405996 is about 25404.8419794338. The cubic root of 645405996 is about 864.1935062551.

The spelling of 645405996 in words is "six hundred forty-five million, four hundred five thousand, nine hundred ninety-six".