20661606 has 24 divisors (see below), whose sum is σ = 51162384. Its totient is φ = 5903280.

The previous prime is 20661587. The next prime is 20661631. The reversal of 20661606 is 60616602.

It is a self number, because there is not a number n which added to its sum of digits gives 20661606.

It is a congruent 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 in 11 ways as a sum of consecutive naturals, for example, 81865 + ... + 82116.

It is an arithmetic number, because the mean of its divisors is an integer number (2131766).

Almost surely, 2^20661606 is an apocalyptic number.

20661606 is an abundant number, since it is smaller than the sum of its proper divisors (30500778).

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

20661606 is a wasteful number, since it uses less digits than its factorization.

20661606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163996 (or 163993 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 20661606 is about 4545.5039324590. The cubic root of 20661606 is about 274.4024756326.

The spelling of 20661606 in words is "twenty million, six hundred sixty-one thousand, six hundred six".