21606602 has 4 divisors (see below), whose sum is σ = 32409906. Its totient is φ = 10803300.

The previous prime is 21606589. The next prime is 21606623. The reversal of 21606602 is 20660612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21335161 + 271441 = 4619^2 + 521^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5401649 + ... + 5401652.

Almost surely, 2^21606602 is an apocalyptic number.

21606602 is a deficient number, since it is larger than the sum of its proper divisors (10803304).

21606602 is a wasteful number, since it uses less digits than its factorization.

21606602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10803303.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21606602 is about 4648.2902232972. The cubic root of 21606602 is about 278.5237009871.

The spelling of 21606602 in words is "twenty-one million, six hundred six thousand, six hundred two".