20775861 has 12 divisors (see below), whose sum is σ = 31044780. Its totient is φ = 13372800.

The previous prime is 20775857. The next prime is 20775883. The reversal of 20775861 is 16857702.

20775861 is a `hidden beast` number, since 2 + 0 + 77 + 586 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3261636 + 17514225 = 1806^2 + 4185^2 .

It is not a de Polignac number, because 20775861 - 2² = 20775857 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20775851) by changing a digit.

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, 39540 + ... + 40061.

It is an arithmetic number, because the mean of its divisors is an integer number (2587065).

Almost surely, 2^20775861 is an apocalyptic number.

It is an amenable number.

20775861 is a deficient number, since it is larger than the sum of its proper divisors (10268919).

20775861 is a wasteful number, since it uses less digits than its factorization.

20775861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79636 (or 79633 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The square root of 20775861 is about 4558.0545192001. The cubic root of 20775861 is about 274.9073450941.

The spelling of 20775861 in words is "twenty million, seven hundred seventy-five thousand, eight hundred sixty-one".