261388877 has 2 divisors, whose sum is σ = 261388878. Its totient is φ = 261388876.

The previous prime is 261388849. The next prime is 261388891. The reversal of 261388877 is 778883162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194574601 + 66814276 = 13949^2 + 8174^2 .

It is a cyclic number.

It is not a de Polignac number, because 261388877 - 2²⁶ = 194280013 is a prime.

It is a super-2 number, since 2×261388877² = 136648290038642258, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261388847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130694438 + 130694439.

It is an arithmetic number, because the mean of its divisors is an integer number (130694439).

Almost surely, 2^261388877 is an apocalyptic number.

It is an amenable number.

261388877 is a deficient number, since it is larger than the sum of its proper divisors (1).

261388877 is an equidigital number, since it uses as much as digits as its factorization.

261388877 is an evil number, because the sum of its binary digits is even.

The product of its digits is 903168, while the sum is 50.

The square root of 261388877 is about 16167.5253826923. The cubic root of 261388877 is about 639.3848883276.

The spelling of 261388877 in words is "two hundred sixty-one million, three hundred eighty-eight thousand, eight hundred seventy-seven".