20756261 has 2 divisors, whose sum is σ = 20756262. Its totient is φ = 20756260.

The previous prime is 20756243. The next prime is 20756273. The reversal of 20756261 is 16265702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18653761 + 2102500 = 4319^2 + 1450^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20756261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20726261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10378130 + 10378131.

It is an arithmetic number, because the mean of its divisors is an integer number (10378131).

Almost surely, 2^20756261 is an apocalyptic number.

It is an amenable number.

20756261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20756261 is an equidigital number, since it uses as much as digits as its factorization.

20756261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 20756261 is about 4555.9039717711. The cubic root of 20756261 is about 274.8208684653.

The spelling of 20756261 in words is "twenty million, seven hundred fifty-six thousand, two hundred sixty-one".