261395969 has 2 divisors, whose sum is σ = 261395970. Its totient is φ = 261395968.

The previous prime is 261395957. The next prime is 261395983. The reversal of 261395969 is 969593162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 183250369 + 78145600 = 13537^2 + 8840^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261395969 is a prime.

It is a super-2 number, since 2×261395969² = 136655705218897922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261395909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130697984 + 130697985.

It is an arithmetic number, because the mean of its divisors is an integer number (130697985).

Almost surely, 2^261395969 is an apocalyptic number.

It is an amenable number.

261395969 is a deficient number, since it is larger than the sum of its proper divisors (1).

261395969 is an equidigital number, since it uses as much as digits as its factorization.

261395969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 787320, while the sum is 50.

The square root of 261395969 is about 16167.7447097609. The cubic root of 261395969 is about 639.3906708698.

The spelling of 261395969 in words is "two hundred sixty-one million, three hundred ninety-five thousand, nine hundred sixty-nine".