261479557 has 2 divisors, whose sum is σ = 261479558. Its totient is φ = 261479556.

The previous prime is 261479549. The next prime is 261479579. The reversal of 261479557 is 755974162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 256032001 + 5447556 = 16001^2 + 2334^2 .

It is a cyclic number.

It is not a de Polignac number, because 261479557 - 2³ = 261479549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261479527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130739778 + 130739779.

It is an arithmetic number, because the mean of its divisors is an integer number (130739779).

Almost surely, 2^261479557 is an apocalyptic number.

It is an amenable number.

261479557 is a deficient number, since it is larger than the sum of its proper divisors (1).

261479557 is an equidigital number, since it uses as much as digits as its factorization.

261479557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 529200, while the sum is 46.

The square root of 261479557 is about 16170.3295266361. The cubic root of 261479557 is about 639.4588174085.

The spelling of 261479557 in words is "two hundred sixty-one million, four hundred seventy-nine thousand, five hundred fifty-seven".