21461708637 has 24 divisors (see below), whose sum is σ = 31253703000. Its totient is φ = 14191106688.

The previous prime is 21461708627. The next prime is 21461708683. The reversal of 21461708637 is 73680716412.

21461708637 is a `hidden beast` number, since 2 + 1 + 4 + 6 + 1 + 7 + 0 + 8 + 637 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1945339236 + 19516369401 = 44106^2 + 139701^2 .

It is not a de Polignac number, because 21461708637 - 2⁴ = 21461708621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21461708592 and 21461708601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21461708627) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 939483 + ... + 962055.

It is an arithmetic number, because the mean of its divisors is an integer number (1302237625).

Almost surely, 2^21461708637 is an apocalyptic number.

It is an amenable number.

21461708637 is a deficient number, since it is larger than the sum of its proper divisors (9791994363).

21461708637 is a wasteful number, since it uses less digits than its factorization.

21461708637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23437 (or 23434 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The spelling of 21461708637 in words is "twenty-one billion, four hundred sixty-one million, seven hundred eight thousand, six hundred thirty-seven".