20861866 has 8 divisors (see below), whose sum is σ = 32056164. Its totient is φ = 10176480.

The previous prime is 20861833. The next prime is 20861891. The reversal of 20861866 is 66816802.

It can be written as a sum of positive squares in 2 ways, for example, as 17816841 + 3045025 = 4221^2 + 1745^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127125 + ... + 127288.

Almost surely, 2^20861866 is an apocalyptic number.

20861866 is a deficient number, since it is larger than the sum of its proper divisors (11194298).

20861866 is a wasteful number, since it uses less digits than its factorization.

20861866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254456.

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 20861866 is about 4567.4791734610. The cubic root of 20861866 is about 275.2861638238.

The spelling of 20861866 in words is "twenty million, eight hundred sixty-one thousand, eight hundred sixty-six".