21606424 has 32 divisors (see below), whose sum is σ = 46473120. Its totient is φ = 9225216.

The previous prime is 21606419. The next prime is 21606437. The reversal of 21606424 is 42460612.

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, 19222 + ... + 20314.

It is an arithmetic number, because the mean of its divisors is an integer number (1452285).

Almost surely, 2^21606424 is an apocalyptic number.

It is an amenable number.

21606424 is an abundant number, since it is smaller than the sum of its proper divisors (24866696).

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

21606424 is a wasteful number, since it uses less digits than its factorization.

21606424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1459 (or 1455 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 21606424 is about 4648.2710764326. The cubic root of 21606424 is about 278.5229361382.

The spelling of 21606424 in words is "twenty-one million, six hundred six thousand, four hundred twenty-four".