21249046815165 has 32 divisors (see below), whose sum is σ = 40681935786240. Its totient is φ = 10461069200448.

The previous prime is 21249046815149. The next prime is 21249046815169. The reversal of 21249046815165 is 56151864094212.

It is a happy number.

21249046815165 is a `hidden beast` number, since 2 + 1 + 2 + 4 + 9 + 0 + 46 + 81 + 516 + 5 = 666.

It is not a de Polignac number, because 21249046815165 - 2⁴ = 21249046815149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249046815169) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6053857737 + ... + 6053861246.

It is an arithmetic number, because the mean of its divisors is an integer number (1271310493320).

Almost surely, 2^{21249046815165} is an apocalyptic number.

It is an amenable number.

21249046815165 is a deficient number, since it is larger than the sum of its proper divisors (19432888971075).

21249046815165 is a wasteful number, since it uses less digits than its factorization.

21249046815165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12107719010 (or 12107719004 counting only the distinct ones).

The product of its (nonzero) digits is 4147200, while the sum is 54.

The spelling of 21249046815165 in words is "twenty-one trillion, two hundred forty-nine billion, forty-six million, eight hundred fifteen thousand, one hundred sixty-five".