21902459 has 4 divisors (see below), whose sum is σ = 23055240. Its totient is φ = 20749680.

The previous prime is 21902431. The next prime is 21902471. The reversal of 21902459 is 95420912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21902459 - 2⁸ = 21902203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21902429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 576362 + ... + 576399.

It is an arithmetic number, because the mean of its divisors is an integer number (5763810).

Almost surely, 2^21902459 is an apocalyptic number.

21902459 is a deficient number, since it is larger than the sum of its proper divisors (1152781).

21902459 is a wasteful number, since it uses less digits than its factorization.

21902459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1152780.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 21902459 is about 4680.0063034146. The cubic root of 21902459 is about 279.7892078459.

The spelling of 21902459 in words is "twenty-one million, nine hundred two thousand, four hundred fifty-nine".