815258261 has 2 divisors, whose sum is σ = 815258262. Its totient is φ = 815258260.

The previous prime is 815258189. The next prime is 815258293. The reversal of 815258261 is 162852518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 814246225 + 1012036 = 28535^2 + 1006^2 .

It is a cyclic number.

It is not a de Polignac number, because 815258261 - 2¹⁰ = 815257237 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (815258761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407629130 + 407629131.

It is an arithmetic number, because the mean of its divisors is an integer number (407629131).

Almost surely, 2^815258261 is an apocalyptic number.

It is an amenable number.

815258261 is a deficient number, since it is larger than the sum of its proper divisors (1).

815258261 is an equidigital number, since it uses as much as digits as its factorization.

815258261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38400, while the sum is 38.

The square root of 815258261 is about 28552.7277330906. The cubic root of 815258261 is about 934.1825186242.

The spelling of 815258261 in words is "eight hundred fifteen million, two hundred fifty-eight thousand, two hundred sixty-one".