20955747121 has 15 divisors (see below), whose sum is σ = 22175245883. Its totient is φ = 19803304800.

The previous prime is 20955747061. The next prime is 20955747139. The reversal of 20955747121 is 12174755902.

The square root of 20955747121 is 144761.

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., 20747233521 + 208513600 = 144039^2 + 14440^2 .

It is not a de Polignac number, because 20955747121 - 2¹³ = 20955738929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20955747181) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 52258521 + ... + 52258921.

Almost surely, 2^20955747121 is an apocalyptic number.

20955747121 is the 144761-st square number.

20955747121 is the 72381-st centered octagonal number.

It is an amenable number.

20955747121 is a deficient number, since it is larger than the sum of its proper divisors (1219498762).

20955747121 is an frugal number, since it uses more digits than its factorization.

20955747121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878 (or 420 counting only the distinct ones).

The product of its (nonzero) digits is 176400, while the sum is 43.

The spelling of 20955747121 in words is "twenty billion, nine hundred fifty-five million, seven hundred forty-seven thousand, one hundred twenty-one".