21900402 has 32 divisors (see below), whose sum is σ = 49708800. Its totient is φ = 7143984.

The previous prime is 21900397. The next prime is 21900419. The reversal of 21900402 is 20400912.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1777 + ... + 6852.

It is an arithmetic number, because the mean of its divisors is an integer number (1553400).

Almost surely, 2^21900402 is an apocalyptic number.

21900402 is an abundant number, since it is smaller than the sum of its proper divisors (27808398).

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

21900402 is a wasteful number, since it uses less digits than its factorization.

21900402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8687 (or 8681 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 21900402 is about 4679.7865335932. The cubic root of 21900402 is about 279.7804486404.

The spelling of 21900402 in words is "twenty-one million, nine hundred thousand, four hundred two".