21901400 has 24 divisors (see below), whose sum is σ = 50921220. Its totient is φ = 8760480.

The previous prime is 21901391. The next prime is 21901403. The reversal of 21901400 is 410912.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21901403) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54554 + ... + 54953.

Almost surely, 2^21901400 is an apocalyptic number.

21901400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21901400 is an abundant number, since it is smaller than the sum of its proper divisors (29019820).

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

21901400 is a wasteful number, since it uses less digits than its factorization.

21901400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109523 (or 109514 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 21901400 is about 4679.8931611737. The cubic root of 21901400 is about 279.7846984353.

The spelling of 21901400 in words is "twenty-one million, nine hundred one thousand, four hundred".