21975424 has 32 divisors (see below), whose sum is σ = 46359000. Its totient is φ = 10340352.

The previous prime is 21975413. The next prime is 21975427. The reversal of 21975424 is 42457912.

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a self number, because there is not a number n which added to its sum of digits gives 21975424.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21975427) 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, 2874 + ... + 7225.

Almost surely, 2^21975424 is an apocalyptic number.

It is an amenable number.

21975424 is an abundant number, since it is smaller than the sum of its proper divisors (24383576).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21975424 is a wasteful number, since it uses less digits than its factorization.

21975424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10130 (or 10118 counting only the distinct ones).

The product of its digits is 20160, while the sum is 34.

The square root of 21975424 is about 4687.7952173703. The cubic root of 21975424 is about 280.0995564344.

The spelling of 21975424 in words is "twenty-one million, nine hundred seventy-five thousand, four hundred twenty-four".