21902387 has 8 divisors (see below), whose sum is σ = 23649360. Its totient is φ = 20164320.

The previous prime is 21902347. The next prime is 21902407. The reversal of 21902387 is 78320912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21902387 - 2⁸ = 21902131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21902317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3437 + ... + 7457.

It is an arithmetic number, because the mean of its divisors is an integer number (2956170).

Almost surely, 2^21902387 is an apocalyptic number.

21902387 is a deficient number, since it is larger than the sum of its proper divisors (1746973).

21902387 is a wasteful number, since it uses less digits than its factorization.

21902387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4453.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21902387 is about 4679.9986111109. The cubic root of 21902387 is about 279.7889012617.

The spelling of 21902387 in words is "twenty-one million, nine hundred two thousand, three hundred eighty-seven".