20813761 has 2 divisors, whose sum is σ = 20813762. Its totient is φ = 20813760.

The previous prime is 20813753. The next prime is 20813791. The reversal of 20813761 is 16731802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13278736 + 7535025 = 3644^2 + 2745^2 .

It is a cyclic number.

It is not a de Polignac number, because 20813761 - 2³ = 20813753 is a prime.

It is equal to p_1318924 and since 20813761 and 1318924 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20813731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10406880 + 10406881.

It is an arithmetic number, because the mean of its divisors is an integer number (10406881).

Almost surely, 2^20813761 is an apocalyptic number.

It is an amenable number.

20813761 is a deficient number, since it is larger than the sum of its proper divisors (1).

20813761 is an equidigital number, since it uses as much as digits as its factorization.

20813761 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 20813761 is about 4562.2101003790. The cubic root of 20813761 is about 275.0744085151.

The spelling of 20813761 in words is "twenty million, eight hundred thirteen thousand, seven hundred sixty-one".