261253687 has 2 divisors, whose sum is σ = 261253688. Its totient is φ = 261253686.

The previous prime is 261253669. The next prime is 261253691. The reversal of 261253687 is 786352162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261253687 - 2²³ = 252865079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261253087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130626843 + 130626844.

It is an arithmetic number, because the mean of its divisors is an integer number (130626844).

Almost surely, 2^261253687 is an apocalyptic number.

261253687 is a deficient number, since it is larger than the sum of its proper divisors (1).

261253687 is an equidigital number, since it uses as much as digits as its factorization.

261253687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 40.

The square root of 261253687 is about 16163.3439300165. The cubic root of 261253687 is about 639.2746396306.

The spelling of 261253687 in words is "two hundred sixty-one million, two hundred fifty-three thousand, six hundred eighty-seven".