21440391162129 has 27 divisors (see below), whose sum is σ = 32001337560699. Its totient is φ = 13832232604560.

The previous prime is 21440391162119. The next prime is 21440391162161. The reversal of 21440391162129 is 92126119304412.

The square root of 21440391162129 is 4630377.

It is a perfect power (a square), and thus also a powerful number.

21440391162129 is a `hidden beast` number, since 2 + 1 + 4 + 4 + 0 + 3 + 9 + 11 + 621 + 2 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 4343985513729 + 17096405648400 = 2084223^2 + 4134780^2 .

It is not a de Polignac number, because 21440391162129 - 2⁵ = 21440391162097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21440391162119) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 430600167 + ... + 430649955.

Almost surely, 2^{21440391162129} is an apocalyptic number.

21440391162129 is the 4630377-th square number.

21440391162129 is the 2315189-th centered octagonal number.

It is an amenable number.

21440391162129 is a deficient number, since it is larger than the sum of its proper divisors (10560946398570).

21440391162129 is an frugal number, since it uses more digits than its factorization.

21440391162129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99646 (or 49823 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 21440391162129 in words is "twenty-one trillion, four hundred forty billion, three hundred ninety-one million, one hundred sixty-two thousand, one hundred twenty-nine".