20970225721 has 9 divisors (see below), whose sum is σ = 21114131311. Its totient is φ = 20827297264.

The previous prime is 20970225673. The next prime is 20970225733. The reversal of 20970225721 is 12752207902.

The square root of 20970225721 is 144811.

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., 18458211321 + 2512014400 = 135861^2 + 50120^2 .

It is not a de Polignac number, because 20970225721 - 2¹³ = 20970217529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20970225751) 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, 25920765 + ... + 25921573.

Almost surely, 2^20970225721 is an apocalyptic number.

20970225721 is the 144811-st square number.

20970225721 is the 72406-th centered octagonal number.

It is an amenable number.

20970225721 is a deficient number, since it is larger than the sum of its proper divisors (143905590).

20970225721 is an frugal number, since it uses more digits than its factorization.

20970225721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1976 (or 988 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 37.

The spelling of 20970225721 in words is "twenty billion, nine hundred seventy million, two hundred twenty-five thousand, seven hundred twenty-one".