261651331 has 2 divisors, whose sum is σ = 261651332. Its totient is φ = 261651330.

The previous prime is 261651319. The next prime is 261651343. The reversal of 261651331 is 133156162.

It is a balanced prime because it is at equal distance from previous prime (261651319) and next prime (261651343).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261651331 is a prime.

It is a super-2 number, since 2×261651331² = 136922838028143122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261651331.

It is not a weakly prime, because it can be changed into another prime (261651361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130825665 + 130825666.

It is an arithmetic number, because the mean of its divisors is an integer number (130825666).

Almost surely, 2^261651331 is an apocalyptic number.

261651331 is a deficient number, since it is larger than the sum of its proper divisors (1).

261651331 is an equidigital number, since it uses as much as digits as its factorization.

261651331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 28.

The square root of 261651331 is about 16175.6400491603. The cubic root of 261651331 is about 639.5988135086.

The spelling of 261651331 in words is "two hundred sixty-one million, six hundred fifty-one thousand, three hundred thirty-one".