20256666 has 8 divisors (see below), whose sum is σ = 40513344. Its totient is φ = 6752220.

The previous prime is 20256659. The next prime is 20256689. The reversal of 20256666 is 66665202.

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

20256666 is an admirable 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, 1688050 + ... + 1688061.

It is an arithmetic number, because the mean of its divisors is an integer number (5064168).

Almost surely, 2^20256666 is an apocalyptic number.

20256666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20256666 is a wasteful number, since it uses less digits than its factorization.

20256666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3376116.

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 20256666 is about 4500.7406057226. The cubic root of 20256666 is about 272.5979941026.

It can be divided in two parts, 20 and 256666, that added together give a triangular number (256686 = T₇₁₆).

The spelling of 20256666 in words is "twenty million, two hundred fifty-six thousand, six hundred sixty-six".