21899605 has 16 divisors (see below), whose sum is σ = 32344704. Its totient is φ = 13861440.

The previous prime is 21899543. The next prime is 21899627. The reversal of 21899605 is 50699812.

It is not a de Polignac number, because 21899605 - 2⁷ = 21899477 is a prime.

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, 23611 + ... + 24520.

It is an arithmetic number, because the mean of its divisors is an integer number (2021544).

Almost surely, 2^21899605 is an apocalyptic number.

It is an amenable number.

21899605 is a deficient number, since it is larger than the sum of its proper divisors (10445099).

21899605 is a wasteful number, since it uses less digits than its factorization.

21899605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48156.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 21899605 is about 4679.7013793617. The cubic root of 21899605 is about 279.7770546735. Note that the first 3 decimals are identical.

The spelling of 21899605 in words is "twenty-one million, eight hundred ninety-nine thousand, six hundred five".