13124222721 has 21 divisors (see below), whose sum is σ = 19681971249. Its totient is φ = 8747419716.

The previous prime is 13124222711. The next prime is 13124222731. The reversal of 13124222721 is 12722242131.

It is a happy number.

The square root of 13124222721 is 114561.

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

It is an interprime number because it is at equal distance from previous prime (13124222711) and next prime (13124222731).

It is not a de Polignac number, because 13124222721 - 2²⁵ = 13090668289 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (13124222711) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 3091026 + ... + 3095268.

Almost surely, 2^13124222721 is an apocalyptic number.

13124222721 is the 114561-st square number.

13124222721 is the 57281-st centered octagonal number.

It is an amenable number.

13124222721 is a deficient number, since it is larger than the sum of its proper divisors (6557748528).

13124222721 is an frugal number, since it uses more digits than its factorization.

13124222721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8504 (or 4246 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

Adding to 13124222721 its reverse (12722242131), we get a palindrome (25846464852).

The spelling of 13124222721 in words is "thirteen billion, one hundred twenty-four million, two hundred twenty-two thousand, seven hundred twenty-one".