21608988 has 24 divisors (see below), whose sum is σ = 50913408. Its totient is φ = 7132656.

The previous prime is 21608987. The next prime is 21609011. The reversal of 21608988 is 88980612.

It is a congruent number.

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, 7506 + ... + 9977.

It is an arithmetic number, because the mean of its divisors is an integer number (2121392).

Almost surely, 2^21608988 is an apocalyptic number.

It is an amenable number.

21608988 is an abundant number, since it is smaller than the sum of its proper divisors (29304420).

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

21608988 is a wasteful number, since it uses less digits than its factorization.

21608988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17593 (or 17591 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 21608988 is about 4648.5468697218. The cubic root of 21608988 is about 278.5339529938.

The spelling of 21608988 in words is "twenty-one million, six hundred eight thousand, nine hundred eighty-eight".