20156265121 has 16 divisors (see below), whose sum is σ = 21473121600. Its totient is φ = 18865363968.

The previous prime is 20156265071. The next prime is 20156265127. The reversal of 20156265121 is 12156265102.

It is a cyclic number.

It is not a de Polignac number, because 20156265121 - 2¹⁵ = 20156232353 is a prime.

It is a super-2 number, since 2×20156265121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20156265127) 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, 2408881 + ... + 2417233.

It is an arithmetic number, because the mean of its divisors is an integer number (1342070100).

Almost surely, 2^20156265121 is an apocalyptic number.

It is an amenable number.

20156265121 is a deficient number, since it is larger than the sum of its proper divisors (1316856479).

20156265121 is a wasteful number, since it uses less digits than its factorization.

20156265121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9888.

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 20156265121 in words is "twenty billion, one hundred fifty-six million, two hundred sixty-five thousand, one hundred twenty-one".