261787013 has 2 divisors, whose sum is σ = 261787014. Its totient is φ = 261787012.

The previous prime is 261786919. The next prime is 261787061. The reversal of 261787013 is 310787162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 181899169 + 79887844 = 13487^2 + 8938^2 .

It is a cyclic number.

It is not a de Polignac number, because 261787013 - 2²⁶ = 194678149 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_14288138 and since 261787013 and 14288138 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261787093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130893506 + 130893507.

It is an arithmetic number, because the mean of its divisors is an integer number (130893507).

Almost surely, 2^261787013 is an apocalyptic number.

It is an amenable number.

261787013 is a deficient number, since it is larger than the sum of its proper divisors (1).

261787013 is an equidigital number, since it uses as much as digits as its factorization.

261787013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14112, while the sum is 35.

The square root of 261787013 is about 16179.8335281918. The cubic root of 261787013 is about 639.7093512608.

The spelling of 261787013 in words is "two hundred sixty-one million, seven hundred eighty-seven thousand, thirteen".