21902412 has 54 divisors (see below), whose sum is σ = 59759028. Its totient is φ = 6225408.

The previous prime is 21902411. The next prime is 21902429. The reversal of 21902412 is 21420912.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21902411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 113388 + ... + 113580.

Almost surely, 2^21902412 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21902412, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29879514).

21902412 is an abundant number, since it is smaller than the sum of its proper divisors (37856616).

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

21902412 is a wasteful number, since it uses less digits than its factorization.

21902412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407 (or 205 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21902412 is about 4680.0012820511. The cubic root of 21902412 is about 279.7890077147.

The spelling of 21902412 in words is "twenty-one million, nine hundred two thousand, four hundred twelve".