21977224 has 32 divisors (see below), whose sum is σ = 43660800. Its totient is φ = 10342080.

The previous prime is 21977191. The next prime is 21977231. The reversal of 21977224 is 42277912.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21977224.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28654 + ... + 29410.

It is an arithmetic number, because the mean of its divisors is an integer number (1364400).

Almost surely, 2^21977224 is an apocalyptic number.

It is an amenable number.

21977224 is a deficient number, since it is larger than the sum of its proper divisors (21683576).

21977224 is a wasteful number, since it uses less digits than its factorization.

21977224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 973 (or 969 counting only the distinct ones).

The product of its digits is 14112, while the sum is 34.

The square root of 21977224 is about 4687.9872013477. The cubic root of 21977224 is about 280.1072038475.

It can be divided in two parts, 21977 and 224, that added together give a square (22201 = 149²).

The spelling of 21977224 in words is "twenty-one million, nine hundred seventy-seven thousand, two hundred twenty-four".