645124524021 has 36 divisors (see below), whose sum is σ = 994860516000. Its totient is φ = 402749601408.

The previous prime is 645124524017. The next prime is 645124524097. The reversal of 645124524021 is 120425421546.

645124524021 is a `hidden beast` number, since 6 + 4 + 5 + 1 + 245 + 2 + 402 + 1 = 666.

It is not a de Polignac number, because 645124524021 - 2² = 645124524017 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645124520021) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 105591 + ... + 1140788.

Almost surely, 2^645124524021 is an apocalyptic number.

It is an amenable number.

645124524021 is a deficient number, since it is larger than the sum of its proper divisors (349735991979).

645124524021 is a wasteful number, since it uses less digits than its factorization.

645124524021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1246618 (or 1246598 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

Adding to 645124524021 its reverse (120425421546), we get a palindrome (765549945567).

The spelling of 645124524021 in words is "six hundred forty-five billion, one hundred twenty-four million, five hundred twenty-four thousand, twenty-one".