261305457 has 32 divisors (see below), whose sum is σ = 413664000. Its totient is φ = 143555328.

The previous prime is 261305437. The next prime is 261305459. The reversal of 261305457 is 754503162.

It is not a de Polignac number, because 261305457 - 2⁶ = 261305393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261305459) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 167919 + ... + 169467.

It is an arithmetic number, because the mean of its divisors is an integer number (12927000).

Almost surely, 2^261305457 is an apocalyptic number.

It is an amenable number.

261305457 is a deficient number, since it is larger than the sum of its proper divisors (152358543).

261305457 is a wasteful number, since it uses less digits than its factorization.

261305457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1865.

The product of its (nonzero) digits is 25200, while the sum is 33.

The square root of 261305457 is about 16164.9453138574. The cubic root of 261305457 is about 639.3168630377.

The spelling of 261305457 in words is "two hundred sixty-one million, three hundred five thousand, four hundred fifty-seven".