21609606 has 32 divisors (see below), whose sum is σ = 44328960. Its totient is φ = 7020864.

The previous prime is 21609589. The next prime is 21609641. The reversal of 21609606 is 60690612.

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, 44875 + ... + 45353.

It is an arithmetic number, because the mean of its divisors is an integer number (1385280).

Almost surely, 2^21609606 is an apocalyptic number.

21609606 is an abundant number, since it is smaller than the sum of its proper divisors (22719354).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21609606 is a wasteful number, since it uses less digits than its factorization.

21609606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660.

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 21609606 is about 4648.6133416321. The cubic root of 21609606 is about 278.5366082523.

The spelling of 21609606 in words is "twenty-one million, six hundred nine thousand, six hundred six".