20791261 has 2 divisors, whose sum is σ = 20791262. Its totient is φ = 20791260.

The previous prime is 20791247. The next prime is 20791273. The reversal of 20791261 is 16219702.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11519236 + 9272025 = 3394^2 + 3045^2 .

It is a cyclic number.

It is not a de Polignac number, because 20791261 - 2⁵ = 20791229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20791291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10395630 + 10395631.

It is an arithmetic number, because the mean of its divisors is an integer number (10395631).

Almost surely, 2^20791261 is an apocalyptic number.

It is an amenable number.

20791261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20791261 is an equidigital number, since it uses as much as digits as its factorization.

20791261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 20791261 is about 4559.7435234890. The cubic root of 20791261 is about 274.9752528695.

The spelling of 20791261 in words is "twenty million, seven hundred ninety-one thousand, two hundred sixty-one".