22991221 has 4 divisors (see below), whose sum is σ = 25081344. Its totient is φ = 20901100.

The previous prime is 22991219. The next prime is 22991233. The reversal of 22991221 is 12219922.

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 22991221 - 2¹ = 22991219 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 22991221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22991321) 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, 1045045 + ... + 1045066.

It is an arithmetic number, because the mean of its divisors is an integer number (6270336).

Almost surely, 2^22991221 is an apocalyptic number.

It is an amenable number.

22991221 is a deficient number, since it is larger than the sum of its proper divisors (2090123).

22991221 is a wasteful number, since it uses less digits than its factorization.

22991221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2090122.

The product of its digits is 1296, while the sum is 28.

The square root of 22991221 is about 4794.9161619365. The cubic root of 22991221 is about 284.3505103252.

The spelling of 22991221 in words is "twenty-two million, nine hundred ninety-one thousand, two hundred twenty-one".