21975408 has 240 divisors, whose sum is σ = 79875840. Its totient is φ = 5660928.

The previous prime is 21975383. The next prime is 21975413. The reversal of 21975408 is 80457912.

21975408 is a `hidden beast` number, since 21 + 97 + 540 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 511035 + ... + 511077.

It is an arithmetic number, because the mean of its divisors is an integer number (332816).

Almost surely, 2^21975408 is an apocalyptic number.

21975408 is a gapful number since it is divisible by the number (28) 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 21975408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39937920).

21975408 is an abundant number, since it is smaller than the sum of its proper divisors (57900432).

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

21975408 is a wasteful number, since it uses less digits than its factorization.

21975408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 68 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 21975408 is about 4687.7935108108. The cubic root of 21975408 is about 280.0994884555.

It can be divided in two parts, 2197 and 5408, that multiplied together give a 5-th power (11881376 = 26⁵).

The spelling of 21975408 in words is "twenty-one million, nine hundred seventy-five thousand, four hundred eight".