637664138421 has 16 divisors (see below), whose sum is σ = 858688093440. Its totient is φ = 420875307200.

The previous prime is 637664138413. The next prime is 637664138437. The reversal of 637664138421 is 124831466736.

It is a cyclic number.

It is not a de Polignac number, because 637664138421 - 2³ = 637664138413 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 (637664138401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5982631 + ... + 6088283.

It is an arithmetic number, because the mean of its divisors is an integer number (53668005840).

Almost surely, 2^637664138421 is an apocalyptic number.

It is an amenable number.

637664138421 is a deficient number, since it is larger than the sum of its proper divisors (221023955019).

637664138421 is a wasteful number, since it uses less digits than its factorization.

637664138421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125676.

The product of its digits is 3483648, while the sum is 51.

The spelling of 637664138421 in words is "six hundred thirty-seven billion, six hundred sixty-four million, one hundred thirty-eight thousand, four hundred twenty-one".