20776813 has 2 divisors, whose sum is σ = 20776814. Its totient is φ = 20776812.

The previous prime is 20776807. The next prime is 20776829. The reversal of 20776813 is 31867702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20448484 + 328329 = 4522^2 + 573^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20776813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20776213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10388406 + 10388407.

It is an arithmetic number, because the mean of its divisors is an integer number (10388407).

Almost surely, 2^20776813 is an apocalyptic number.

It is an amenable number.

20776813 is a deficient number, since it is larger than the sum of its proper divisors (1).

20776813 is an equidigital number, since it uses as much as digits as its factorization.

20776813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14112, while the sum is 34.

The square root of 20776813 is about 4558.1589485230. The cubic root of 20776813 is about 274.9115440022.

The spelling of 20776813 in words is "twenty million, seven hundred seventy-six thousand, eight hundred thirteen".