21875424 has 24 divisors (see below), whose sum is σ = 57423240. Its totient is φ = 7291776.

The previous prime is 21875423. The next prime is 21875437. The reversal of 21875424 is 42457812.

It is a tau number, because it is divible by the number of its divisors (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21875423) 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, 113839 + ... + 114030.

It is an arithmetic number, because the mean of its divisors is an integer number (2392635).

Almost surely, 2^21875424 is an apocalyptic number.

21875424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21875424 is an abundant number, since it is smaller than the sum of its proper divisors (35547816).

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

21875424 is a wasteful number, since it uses less digits than its factorization.

21875424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227882 (or 227874 counting only the distinct ones).

The product of its digits is 17920, while the sum is 33.

The square root of 21875424 is about 4677.1170607544. The cubic root of 21875424 is about 279.6740424577.

The spelling of 21875424 in words is "twenty-one million, eight hundred seventy-five thousand, four hundred twenty-four".