261367531 has 4 divisors (see below), whose sum is σ = 263680632. Its totient is φ = 259054432.

The previous prime is 261367511. The next prime is 261367577. The reversal of 261367531 is 135763162.

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

It is a cyclic number.

It is not a de Polignac number, because 261367531 - 2⁵ = 261367499 is a prime.

It is a super-2 number, since 2×261367531² = 136625972522071922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261367511) 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, 1156381 + ... + 1156606.

It is an arithmetic number, because the mean of its divisors is an integer number (65920158).

Almost surely, 2^261367531 is an apocalyptic number.

261367531 is a deficient number, since it is larger than the sum of its proper divisors (2313101).

261367531 is a wasteful number, since it uses less digits than its factorization.

261367531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2313100.

The product of its digits is 22680, while the sum is 34.

The square root of 261367531 is about 16166.8652187120. The cubic root of 261367531 is about 639.3674829946.

The spelling of 261367531 in words is "two hundred sixty-one million, three hundred sixty-seven thousand, five hundred thirty-one".