21606452 has 18 divisors (see below), whose sum is σ = 43984962. Its totient is φ = 9259824.

The previous prime is 21606443. The next prime is 21606469. The reversal of 21606452 is 25460612.

It can be written as a sum of positive squares in only one way, i.e., 21473956 + 132496 = 4634^2 + 364^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54923 + ... + 55314.

It is an arithmetic number, because the mean of its divisors is an integer number (2443609).

Almost surely, 2^21606452 is an apocalyptic number.

It is an amenable number.

21606452 is an abundant number, since it is smaller than the sum of its proper divisors (22378510).

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

21606452 is a wasteful number, since it uses less digits than its factorization.

21606452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110255 (or 110246 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 21606452 is about 4648.2740883042. The cubic root of 21606452 is about 278.5230564518.

The spelling of 21606452 in words is "twenty-one million, six hundred six thousand, four hundred fifty-two".