21616910 has 16 divisors (see below), whose sum is σ = 44469216. Its totient is φ = 7411488.

The previous prime is 21616909. The next prime is 21616921. The reversal of 21616910 is 1961612.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21616910.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154337 + ... + 154476.

It is an arithmetic number, because the mean of its divisors is an integer number (2779326).

Almost surely, 2^21616910 is an apocalyptic number.

21616910 is an abundant number, since it is smaller than the sum of its proper divisors (22852306).

21616910 is a wasteful number, since it uses less digits than its factorization.

21616910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308827.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 21616910 is about 4649.3988858776. The cubic root of 21616910 is about 278.5679863073.

The spelling of 21616910 in words is "twenty-one million, six hundred sixteen thousand, nine hundred ten".