21121504513365 has 16 divisors (see below), whose sum is σ = 33964228368000. Its totient is φ = 11208195358272.

The previous prime is 21121504513349. The next prime is 21121504513381. The reversal of 21121504513365 is 56331540512112.

It is an interprime number because it is at equal distance from previous prime (21121504513349) and next prime (21121504513381).

It is not a de Polignac number, because 21121504513365 - 2⁴ = 21121504513349 is a prime.

It is a super-2 number, since 2×21121504513365² (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 15 ways as a sum of consecutive naturals, for example, 3537937470 + ... + 3537943439.

It is an arithmetic number, because the mean of its divisors is an integer number (2122764273000).

Almost surely, 2^{21121504513365} is an apocalyptic number.

It is an amenable number.

21121504513365 is a deficient number, since it is larger than the sum of its proper divisors (12842723854635).

21121504513365 is a wasteful number, since it uses less digits than its factorization.

21121504513365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7075881116.

The product of its (nonzero) digits is 108000, while the sum is 39.

The spelling of 21121504513365 in words is "twenty-one trillion, one hundred twenty-one billion, five hundred four million, five hundred thirteen thousand, three hundred sixty-five".