21242604 has 12 divisors (see below), whose sum is σ = 49566104. Its totient is φ = 7080864.

The previous prime is 21242591. The next prime is 21242629. The reversal of 21242604 is 40624212.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 885097 + ... + 885120.

Almost surely, 2^21242604 is an apocalyptic number.

It is an amenable number.

21242604 is an abundant number, since it is smaller than the sum of its proper divisors (28323500).

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

21242604 is a wasteful number, since it uses less digits than its factorization.

21242604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1770224 (or 1770222 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 21242604 is about 4608.9699499997. The cubic root of 21242604 is about 276.9507747462.

Adding to 21242604 its reverse (40624212), we get a palindrome (61866816).

The spelling of 21242604 in words is "twenty-one million, two hundred forty-two thousand, six hundred four".