22179991 has 4 divisors (see below), whose sum is σ = 22329000. Its totient is φ = 22030984.

The previous prime is 22179977. The next prime is 22180009. The reversal of 22179991 is 19997122.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19997122 = 2 ⋅9998561.

It is a cyclic number.

It is not a de Polignac number, because 22179991 - 2⁷ = 22179863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22179901) 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, 74281 + ... + 74578.

It is an arithmetic number, because the mean of its divisors is an integer number (5582250).

Almost surely, 2^22179991 is an apocalyptic number.

22179991 is a deficient number, since it is larger than the sum of its proper divisors (149009).

22179991 is a wasteful number, since it uses less digits than its factorization.

22179991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149008.

The product of its digits is 20412, while the sum is 40.

The square root of 22179991 is about 4709.5637802242. The cubic root of 22179991 is about 280.9660128682.

The spelling of 22179991 in words is "twenty-two million, one hundred seventy-nine thousand, nine hundred ninety-one".