261512761 has 2 divisors, whose sum is σ = 261512762. Its totient is φ = 261512760.

The previous prime is 261512743. The next prime is 261512773. The reversal of 261512761 is 167215162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 214329600 + 47183161 = 14640^2 + 6869^2 .

It is a cyclic number.

It is not a de Polignac number, because 261512761 - 2⁵ = 261512729 is a prime.

It is not a weakly prime, because it can be changed into another prime (261512701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130756380 + 130756381.

It is an arithmetic number, because the mean of its divisors is an integer number (130756381).

Almost surely, 2^261512761 is an apocalyptic number.

It is an amenable number.

261512761 is a deficient number, since it is larger than the sum of its proper divisors (1).

261512761 is an equidigital number, since it uses as much as digits as its factorization.

261512761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5040, while the sum is 31.

The square root of 261512761 is about 16171.3561892625. The cubic root of 261512761 is about 639.4858835039.

It can be divided in two parts, 2615 and 12761, that added together give a square (15376 = 124²).

The spelling of 261512761 in words is "two hundred sixty-one million, five hundred twelve thousand, seven hundred sixty-one".