21252564121505 has 16 divisors (see below), whose sum is σ = 26846102445120. Its totient is φ = 16106751517248.

The previous prime is 21252564121463. The next prime is 21252564121507. The reversal of 21252564121505 is 50512146525212.

It is a cyclic number.

It is not a de Polignac number, because 21252564121505 - 2²⁴ = 21252547344289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21252564121507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 240539 + ... + 6524031.

It is an arithmetic number, because the mean of its divisors is an integer number (1677881402820).

Almost surely, 2^{21252564121505} is an apocalyptic number.

It is an amenable number.

21252564121505 is a deficient number, since it is larger than the sum of its proper divisors (5593538323615).

21252564121505 is a wasteful number, since it uses less digits than its factorization.

21252564121505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6319120.

The product of its (nonzero) digits is 240000, while the sum is 41.

The spelling of 21252564121505 in words is "twenty-one trillion, two hundred fifty-two billion, five hundred sixty-four million, one hundred twenty-one thousand, five hundred five".