645636080 has 20 divisors (see below), whose sum is σ = 1501104072. Its totient is φ = 258254400.

The previous prime is 645636073. The next prime is 645636083. The reversal of 645636080 is 80636546.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645636083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4035146 + ... + 4035305.

Almost surely, 2^645636080 is an apocalyptic number.

It is an amenable number.

645636080 is an abundant number, since it is smaller than the sum of its proper divisors (855467992).

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

645636080 is a wasteful number, since it uses less digits than its factorization.

645636080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8070464 (or 8070458 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 38.

The square root of 645636080 is about 25409.3699252854. The cubic root of 645636080 is about 864.2961876042.

The spelling of 645636080 in words is "six hundred forty-five million, six hundred thirty-six thousand, eighty".