261032581 has 4 divisors (see below), whose sum is σ = 263617164. Its totient is φ = 258448000.

The previous prime is 261032573. The next prime is 261032627. The reversal of 261032581 is 185230162.

261032581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 213890625 + 47141956 = 14625^2 + 6866^2 .

It is a cyclic number.

It is not a de Polignac number, because 261032581 - 2³ = 261032573 is a prime.

It is a super-2 number, since 2×261032581² = 136276016687043122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261032381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1292140 + ... + 1292341.

It is an arithmetic number, because the mean of its divisors is an integer number (65904291).

Almost surely, 2^261032581 is an apocalyptic number.

It is an amenable number.

261032581 is a deficient number, since it is larger than the sum of its proper divisors (2584583).

261032581 is a wasteful number, since it uses less digits than its factorization.

261032581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2584582.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 261032581 is about 16156.5027465724. The cubic root of 261032581 is about 639.0942436405.

The spelling of 261032581 in words is "two hundred sixty-one million, thirty-two thousand, five hundred eighty-one".