21121154634015 has 64 divisors (see below), whose sum is σ = 39060506880000. Its totient is φ = 10815419631744.

The previous prime is 21121154633987. The next prime is 21121154634029. The reversal of 21121154634015 is 51043645112112.

21121154634015 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 1 + 1 + 5 + 4 + 634 + 0 + 15 = 666.

It is not a de Polignac number, because 21121154634015 - 2⁹ = 21121154633503 is a prime.

It is a super-2 number, since 2×21121154634015² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 14368855 + ... + 15770424.

It is an arithmetic number, because the mean of its divisors is an integer number (610320420000).

Almost surely, 2^{21121154634015} is an apocalyptic number.

21121154634015 is a deficient number, since it is larger than the sum of its proper divisors (17939352245985).

21121154634015 is a wasteful number, since it uses less digits than its factorization.

21121154634015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30139501 (or 30139495 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

Adding to 21121154634015 its reverse (51043645112112), we get a palindrome (72164799746127).

The spelling of 21121154634015 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred fifty-four million, six hundred thirty-four thousand, fifteen".