636264021 has 16 divisors (see below), whose sum is σ = 855841280. Its totient is φ = 420441840.

The previous prime is 636264017. The next prime is 636264037. The reversal of 636264021 is 120462636.

It is not a de Polignac number, because 636264021 - 2² = 636264017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 636264021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636264011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 487656 + ... + 488958.

It is an arithmetic number, because the mean of its divisors is an integer number (53490080).

Almost surely, 2^636264021 is an apocalyptic number.

It is an amenable number.

636264021 is a deficient number, since it is larger than the sum of its proper divisors (219577259).

636264021 is a wasteful number, since it uses less digits than its factorization.

636264021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2616.

The product of its (nonzero) digits is 10368, while the sum is 30.

The square root of 636264021 is about 25224.2744395156. The cubic root of 636264021 is about 860.0937436121.

The spelling of 636264021 in words is "six hundred thirty-six million, two hundred sixty-four thousand, twenty-one".