20669556 has 12 divisors (see below), whose sum is σ = 48228992. Its totient is φ = 6889848.

The previous prime is 20669543. The next prime is 20669563. The reversal of 20669556 is 65596602.

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

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 3 ways as a sum of consecutive naturals, for example, 861220 + ... + 861243.

Almost surely, 2^20669556 is an apocalyptic number.

It is an amenable number.

20669556 is an abundant number, since it is smaller than the sum of its proper divisors (27559436).

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

20669556 is a wasteful number, since it uses less digits than its factorization.

20669556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1722470 (or 1722468 counting only the distinct ones).

The product of its (nonzero) digits is 97200, while the sum is 39.

The square root of 20669556 is about 4546.3783388539. The cubic root of 20669556 is about 274.4376652165.

The spelling of 20669556 in words is "twenty million, six hundred sixty-nine thousand, five hundred fifty-six".