21506137637144 has 16 divisors (see below), whose sum is σ = 42696008544600. Its totient is φ = 10120535358592.

The previous prime is 21506137637123. The next prime is 21506137637177. The reversal of 21506137637144 is 44173673160512.

It is a super-2 number, since 2×21506137637144² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21506137637092 and 21506137637101.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79066682354 + ... + 79066682625.

Almost surely, 2^{21506137637144} is an apocalyptic number.

It is an amenable number.

21506137637144 is a deficient number, since it is larger than the sum of its proper divisors (21189870907456).

21506137637144 is a wasteful number, since it uses less digits than its factorization.

21506137637144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158133365002 (or 158133364998 counting only the distinct ones).

The product of its (nonzero) digits is 2540160, while the sum is 50.

The spelling of 21506137637144 in words is "twenty-one trillion, five hundred six billion, one hundred thirty-seven million, six hundred thirty-seven thousand, one hundred forty-four".