21875000 has 72 divisors (see below), whose sum is σ = 58593720. Its totient is φ = 7500000.

The previous prime is 21874999. The next prime is 21875033. The reversal of 21875000 is 57812.

It is a nialpdrome in base 5.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3124997 + ... + 3125003.

Almost surely, 2^21875000 is an apocalyptic number.

21875000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21875000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29296860).

21875000 is an abundant number, since it is smaller than the sum of its proper divisors (36718720).

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

21875000 is an frugal number, since it uses more digits than its factorization.

21875000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53 (or 14 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 21875000 is about 4677.0717334674. The cubic root of 21875000 is about 279.6722355203.

The spelling of 21875000 in words is "twenty-one million, eight hundred seventy-five thousand".