261272405 has 16 divisors (see below), whose sum is σ = 335709360. Its totient is φ = 194506752.

The previous prime is 261272383. The next prime is 261272411. The reversal of 261272405 is 504272162.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 18722929 + 242549476 = 4327^2 + 15574^2 .

It is a cyclic number.

It is not a de Polignac number, because 261272405 - 2¹⁸ = 261010261 is a prime.

It is a super-2 number, since 2×261272405² = 136526539228968050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9704 + ... + 24833.

It is an arithmetic number, because the mean of its divisors is an integer number (20981835).

Almost surely, 2^261272405 is an apocalyptic number.

It is an amenable number.

261272405 is a deficient number, since it is larger than the sum of its proper divisors (74436955).

261272405 is a wasteful number, since it uses less digits than its factorization.

261272405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34648.

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 261272405 is about 16163.9229458693. The cubic root of 261272405 is about 639.2899066011.

The spelling of 261272405 in words is "two hundred sixty-one million, two hundred seventy-two thousand, four hundred five".