21608986 has 16 divisors (see below), whose sum is σ = 37673280. Its totient is φ = 9103680.

The previous prime is 21608969. The next prime is 21608987. The reversal of 21608986 is 68980612.

It is not an unprimeable number, because it can be changed into a prime (21608987) 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, 12255 + ... + 13906.

It is an arithmetic number, because the mean of its divisors is an integer number (2354580).

Almost surely, 2^21608986 is an apocalyptic number.

21608986 is a deficient number, since it is larger than the sum of its proper divisors (16064294).

21608986 is a wasteful number, since it uses less digits than its factorization.

21608986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26229.

The product of its (nonzero) digits is 41472, while the sum is 40.

The square root of 21608986 is about 4648.5466546008. The cubic root of 21608986 is about 278.5339444007.

The spelling of 21608986 in words is "twenty-one million, six hundred eight thousand, nine hundred eighty-six".