645994899372 has 24 divisors (see below), whose sum is σ = 1529818768576. Its totient is φ = 212117727888.

The previous prime is 645994899353. The next prime is 645994899377. The reversal of 645994899372 is 273998499546.

It is a junction number, because it is equal to n+sod(n) for n = 645994899294 and 645994899303.

It is not an unprimeable number, because it can be changed into a prime (645994899377) 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, 401737318 + ... + 401738925.

Almost surely, 2^645994899372 is an apocalyptic number.

It is an amenable number.

645994899372 is an abundant number, since it is smaller than the sum of its proper divisors (883823869204).

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

645994899372 is a wasteful number, since it uses less digits than its factorization.

645994899372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803476317 (or 803476315 counting only the distinct ones).

The product of its digits is 1058158080, while the sum is 75.

The spelling of 645994899372 in words is "six hundred forty-five billion, nine hundred ninety-four million, eight hundred ninety-nine thousand, three hundred seventy-two".