22161531 has 16 divisors (see below), whose sum is σ = 34020864. Its totient is φ = 12569664.

The previous prime is 22161527. The next prime is 22161533. The reversal of 22161531 is 13516122.

It is not a de Polignac number, because 22161531 - 2² = 22161527 is a prime.

It is a super-2 number, since 2×22161531² = 982266912527922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 22161498 and 22161507.

It is not an unprimeable number, because it can be changed into a prime (22161533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 975 + ... + 6728.

It is an arithmetic number, because the mean of its divisors is an integer number (2126304).

Almost surely, 2^22161531 is an apocalyptic number.

22161531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

22161531 is a deficient number, since it is larger than the sum of its proper divisors (11859333).

22161531 is a wasteful number, since it uses less digits than its factorization.

22161531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7850.

The product of its digits is 360, while the sum is 21.

The square root of 22161531 is about 4707.6035304601. The cubic root of 22161531 is about 280.8880436124. Note that the first 3 decimals are identical.

Adding to 22161531 its reverse (13516122), we get a palindrome (35677653).

The spelling of 22161531 in words is "twenty-two million, one hundred sixty-one thousand, five hundred thirty-one".