21990604 has 6 divisors (see below), whose sum is σ = 38483564. Its totient is φ = 10995300.

The previous prime is 21990589. The next prime is 21990611. The reversal of 21990604 is 40609912.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2748822 + ... + 2748829.

Almost surely, 2^21990604 is an apocalyptic number.

It is an amenable number.

21990604 is a deficient number, since it is larger than the sum of its proper divisors (16492960).

21990604 is a wasteful number, since it uses less digits than its factorization.

21990604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5497655 (or 5497653 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21990604 is about 4689.4140358898. The cubic root of 21990604 is about 280.1640365343.

The spelling of 21990604 in words is "twenty-one million, nine hundred ninety thousand, six hundred four".