15422907721 has 27 divisors (see below), whose sum is σ = 17191592607. Its totient is φ = 13829687040.

The previous prime is 15422907719. The next prime is 15422907817. The reversal of 15422907721 is 12770922451.

The square root of 15422907721 is 124189.

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

It can be written as a sum of positive squares in 13 ways, for example, as 12042648121 + 3380259600 = 109739^2 + 58140^2 .

It is not a de Polignac number, because 15422907721 - 2¹ = 15422907719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15422907701) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 66192621 + ... + 66192853.

Almost surely, 2^15422907721 is an apocalyptic number.

15422907721 is the 124189-th square number.

15422907721 is the 62095-th centered octagonal number.

It is an amenable number.

15422907721 is a deficient number, since it is larger than the sum of its proper divisors (1768684886).

15422907721 is an frugal number, since it uses more digits than its factorization.

15422907721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 40.

The spelling of 15422907721 in words is "fifteen billion, four hundred twenty-two million, nine hundred seven thousand, seven hundred twenty-one".