21668602 has 8 divisors (see below), whose sum is σ = 32621076. Its totient is φ = 10794912.

The previous prime is 21668593. The next prime is 21668609. The reversal of 21668602 is 20686612.

It can be written as a sum of positive squares in 2 ways, for example, as 18567481 + 3101121 = 4309^2 + 1761^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21668609) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 19003 + ... + 20110.

Almost surely, 2^21668602 is an apocalyptic number.

21668602 is a deficient number, since it is larger than the sum of its proper divisors (10952474).

21668602 is a wasteful number, since it uses less digits than its factorization.

21668602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39392.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 21668602 is about 4654.9545647622. The cubic root of 21668602 is about 278.7898538739.

The spelling of 21668602 in words is "twenty-one million, six hundred sixty-eight thousand, six hundred two".