123644636421 has 8 divisors (see below), whose sum is σ = 166491788064. Its totient is φ = 81613621200.

The previous prime is 123644636407. The next prime is 123644636443. The reversal of 123644636421 is 124636446321.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 123644636421 - 2³¹ = 121497152773 is a prime.

It is a super-2 number, since 2×123644636421² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123644636471) 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 7 ways as a sum of consecutive naturals, for example, 204033751 + ... + 204034356.

It is an arithmetic number, because the mean of its divisors is an integer number (20811473508).

Almost surely, 2^123644636421 is an apocalyptic number.

It is an amenable number.

123644636421 is a deficient number, since it is larger than the sum of its proper divisors (42847151643).

123644636421 is a wasteful number, since it uses less digits than its factorization.

123644636421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408068211.

The product of its digits is 497664, while the sum is 42.

The spelling of 123644636421 in words is "one hundred twenty-three billion, six hundred forty-four million, six hundred thirty-six thousand, four hundred twenty-one".