261954131 has 2 divisors, whose sum is σ = 261954132. Its totient is φ = 261954130.

The previous prime is 261954113. The next prime is 261954163. The reversal of 261954131 is 131459162.

Together with previous prime (261954113) it forms an Ormiston pair, because they use the same digits, order apart.

It is an a-pointer prime, because the next prime (261954163) can be obtained adding 261954131 to its sum of digits (32).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261954131 is a prime.

It is a super-2 number, since 2×261954131² = 137239933495930322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (261954181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130977065 + 130977066.

It is an arithmetic number, because the mean of its divisors is an integer number (130977066).

Almost surely, 2^261954131 is an apocalyptic number.

261954131 is a deficient number, since it is larger than the sum of its proper divisors (1).

261954131 is an equidigital number, since it uses as much as digits as its factorization.

261954131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 32.

The square root of 261954131 is about 16184.9970960764. The cubic root of 261954131 is about 639.8454468923.

The spelling of 261954131 in words is "two hundred sixty-one million, nine hundred fifty-four thousand, one hundred thirty-one".