22137391991521 has 9 divisors (see below), whose sum is σ = 23516276460499. Its totient is φ = 20835117181984.

The previous prime is 22137391991509. The next prime is 22137391991569. The reversal of 22137391991521 is 12519919373122.

The square root of 22137391991521 is 4705039.

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., 17234993765025 + 4902398226496 = 4151505^2 + 2214136^2 .

It is not a de Polignac number, because 22137391991521 - 2⁹ = 22137391991009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22137391991501) 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, 79847280 + ... + 80124046.

Almost surely, 2^{22137391991521} is an apocalyptic number.

22137391991521 is the 4705039-th square number.

22137391991521 is the 2352520-th centered octagonal number.

It is an amenable number.

22137391991521 is a deficient number, since it is larger than the sum of its proper divisors (1378884468978).

22137391991521 is an frugal number, since it uses more digits than its factorization.

22137391991521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553568 (or 276784 counting only the distinct ones).

The product of its digits is 1837080, while the sum is 55.

The spelling of 22137391991521 in words is "twenty-two trillion, one hundred thirty-seven billion, three hundred ninety-one million, nine hundred ninety-one thousand, five hundred twenty-one".