21606908 has 6 divisors (see below), whose sum is σ = 37812096. Its totient is φ = 10803452.

The previous prime is 21606899. The next prime is 21606917. The reversal of 21606908 is 80960612.

It is an interprime number because it is at equal distance from previous prime (21606899) and next prime (21606917).

It is a super-4 number, since 4×21606908⁴ (a number of 30 digits) contains 4444 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2700860 + ... + 2700867.

It is an arithmetic number, because the mean of its divisors is an integer number (6302016).

Almost surely, 2^21606908 is an apocalyptic number.

It is an amenable number.

21606908 is a deficient number, since it is larger than the sum of its proper divisors (16205188).

21606908 is a wasteful number, since it uses less digits than its factorization.

21606908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5401731 (or 5401729 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 21606908 is about 4648.3231385092. The cubic root of 21606908 is about 278.5250158298.

The spelling of 21606908 in words is "twenty-one million, six hundred six thousand, nine hundred eight".