22721131 has 4 divisors (see below), whose sum is σ = 23917000. Its totient is φ = 21525264.

The previous prime is 22721117. The next prime is 22721137. The reversal of 22721131 is 13112722.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 22721131 - 2⁵ = 22721099 is a prime.

It is a super-2 number, since 2×22721131² = 1032499587838322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 1195849 = 22721131 / (2 + 2 + 7 + 2 + 1 + 1 + 3 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 22721099 and 22721108.

It is not an unprimeable number, because it can be changed into a prime (22721137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 597906 + ... + 597943.

It is an arithmetic number, because the mean of its divisors is an integer number (5979250).

Almost surely, 2^22721131 is an apocalyptic number.

22721131 is a deficient number, since it is larger than the sum of its proper divisors (1195869).

22721131 is a wasteful number, since it uses less digits than its factorization.

22721131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1195868.

The product of its digits is 168, while the sum is 19.

The square root of 22721131 is about 4766.6687529133. The cubic root of 22721131 is about 283.2326496546.

Adding to 22721131 its reverse (13112722), we get a palindrome (35833853).

It can be divided in two parts, 2272 and 1131, that added together give a triangular number (3403 = T₈₂).

The spelling of 22721131 in words is "twenty-two million, seven hundred twenty-one thousand, one hundred thirty-one".