20786977 has 4 divisors (see below), whose sum is σ = 20803140. Its totient is φ = 20770816.

The previous prime is 20786947. The next prime is 20786981. The reversal of 20786977 is 77968702.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3845521 + 16941456 = 1961^2 + 4116^2 .

It is a cyclic number.

It is not a de Polignac number, because 20786977 - 2²³ = 12398369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20786947) 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 3 ways as a sum of consecutive naturals, for example, 5968 + ... + 8785.

It is an arithmetic number, because the mean of its divisors is an integer number (5200785).

Almost surely, 2^20786977 is an apocalyptic number.

It is an amenable number.

20786977 is a deficient number, since it is larger than the sum of its proper divisors (16163).

20786977 is a wasteful number, since it uses less digits than its factorization.

20786977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16162.

The product of its (nonzero) digits is 296352, while the sum is 46.

The square root of 20786977 is about 4559.2737360242. The cubic root of 20786977 is about 274.9563655286.

The spelling of 20786977 in words is "twenty million, seven hundred eighty-six thousand, nine hundred seventy-seven".