22539981 has 4 divisors (see below), whose sum is σ = 30053312. Its totient is φ = 15026652.

The previous prime is 22539973. The next prime is 22539983. The reversal of 22539981 is 18993522.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 22539981 - 2³ = 22539973 is a prime.

It is a super-2 number, since 2×22539981² = 1016101486960722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22539983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3756661 + ... + 3756666.

It is an arithmetic number, because the mean of its divisors is an integer number (7513328).

Almost surely, 2^22539981 is an apocalyptic number.

It is an amenable number.

22539981 is a deficient number, since it is larger than the sum of its proper divisors (7513331).

22539981 is an equidigital number, since it uses as much as digits as its factorization.

22539981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7513330.

The product of its digits is 38880, while the sum is 39.

The square root of 22539981 is about 4747.6289871893. The cubic root of 22539981 is about 282.4779255469.

The spelling of 22539981 in words is "twenty-two million, five hundred thirty-nine thousand, nine hundred eighty-one".