21013156848121 has 9 divisors (see below), whose sum is σ = 21132029786511. Its totient is φ = 20894948956464.

The previous prime is 21013156848107. The next prime is 21013156848161. The reversal of 21013156848121 is 12184865131012.

The square root of 21013156848121 is 4584011.

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

It can be written as a sum of positive squares in only one way, i.e., 20983627862521 + 29528985600 = 4580789^2 + 171840^2 .

It is not a de Polignac number, because 21013156848121 - 2²⁵ = 21013123293689 is a prime.

It is a super-2 number, since 2×21013156848121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21013156848161) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 820525165 + ... + 820550773.

Almost surely, 2^{21013156848121} is an apocalyptic number.

21013156848121 is the 4584011-st square number.

21013156848121 is the 2292006-th centered octagonal number.

It is an amenable number.

21013156848121 is a deficient number, since it is larger than the sum of its proper divisors (118872938390).

21013156848121 is an frugal number, since it uses more digits than its factorization.

21013156848121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51576 (or 25788 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 43.

The spelling of 21013156848121 in words is "twenty-one trillion, thirteen billion, one hundred fifty-six million, eight hundred forty-eight thousand, one hundred twenty-one".