261651319 has 2 divisors, whose sum is σ = 261651320. Its totient is φ = 261651318.

The previous prime is 261651293. The next prime is 261651331. The reversal of 261651319 is 913156162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261651319 - 2⁵ = 261651287 is a prime.

It is a super-2 number, since 2×261651319² = 136922825468879522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261651359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130825659 + 130825660.

It is an arithmetic number, because the mean of its divisors is an integer number (130825660).

Almost surely, 2^261651319 is an apocalyptic number.

261651319 is a deficient number, since it is larger than the sum of its proper divisors (1).

261651319 is an equidigital number, since it uses as much as digits as its factorization.

261651319 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 34.

The square root of 261651319 is about 16175.6396782322. The cubic root of 261651319 is about 639.5988037308.

It can be divided in two parts, 2616 and 51319, that added together give a palindrome (53935).

The spelling of 261651319 in words is "two hundred sixty-one million, six hundred fifty-one thousand, three hundred nineteen".