261995311 has 2 divisors, whose sum is σ = 261995312. Its totient is φ = 261995310.

The previous prime is 261995287. The next prime is 261995329. The reversal of 261995311 is 113599162.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261995311 - 2¹⁵ = 261962543 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261995011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130997655 + 130997656.

It is an arithmetic number, because the mean of its divisors is an integer number (130997656).

Almost surely, 2^261995311 is an apocalyptic number.

261995311 is a deficient number, since it is larger than the sum of its proper divisors (1).

261995311 is an equidigital number, since it uses as much as digits as its factorization.

261995311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14580, while the sum is 37.

The square root of 261995311 is about 16186.2692118969. The cubic root of 261995311 is about 639.8789736970.

The spelling of 261995311 in words is "two hundred sixty-one million, nine hundred ninety-five thousand, three hundred eleven".