20806455861 has 24 divisors (see below), whose sum is σ = 30446732160. Its totient is φ = 13689748800.

The previous prime is 20806455827. The next prime is 20806455869. The reversal of 20806455861 is 16855460802.

20806455861 is a `hidden beast` number, since 2 + 0 + 8 + 0 + 64 + 5 + 586 + 1 = 666.

It is not a de Polignac number, because 20806455861 - 2¹¹ = 20806453813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806455869) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2392441 + ... + 2401121.

It is an arithmetic number, because the mean of its divisors is an integer number (1268613840).

Almost surely, 2^20806455861 is an apocalyptic number.

It is an amenable number.

20806455861 is a deficient number, since it is larger than the sum of its proper divisors (9640276299).

20806455861 is a wasteful number, since it uses less digits than its factorization.

20806455861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12137 (or 12134 counting only the distinct ones).

The product of its (nonzero) digits is 460800, while the sum is 45.

The spelling of 20806455861 in words is "twenty billion, eight hundred six million, four hundred fifty-five thousand, eight hundred sixty-one".