21131623647 has 12 divisors (see below), whose sum is σ = 30793576944. Its totient is φ = 13963078080.

The previous prime is 21131623627. The next prime is 21131623657. The reversal of 21131623647 is 74632613112.

21131623647 is a `hidden beast` number, since 2 + 1 + 1 + 3 + 1 + 6 + 2 + 3 + 647 = 666.

It is not a de Polignac number, because 21131623647 - 2²⁰ = 21130575071 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131623607) 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 11 ways as a sum of consecutive naturals, for example, 10388179 + ... + 10390212.

It is an arithmetic number, because the mean of its divisors is an integer number (2566131412).

Almost surely, 2^21131623647 is an apocalyptic number.

21131623647 is a deficient number, since it is larger than the sum of its proper divisors (9661953297).

21131623647 is a wasteful number, since it uses less digits than its factorization.

21131623647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20778510 (or 20778507 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The spelling of 21131623647 in words is "twenty-one billion, one hundred thirty-one million, six hundred twenty-three thousand, six hundred forty-seven".