261011331 has 12 divisors (see below), whose sum is σ = 430875952. Its totient is φ = 149149296.

The previous prime is 261011327. The next prime is 261011347. The reversal of 261011331 is 133110162.

It is not a de Polignac number, because 261011331 - 2² = 261011327 is a prime.

It is a super-3 number, since 3×261011331³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261011381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2071456 + ... + 2071581.

Almost surely, 2^261011331 is an apocalyptic number.

261011331 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

261011331 is a deficient number, since it is larger than the sum of its proper divisors (169864621).

261011331 is a wasteful number, since it uses less digits than its factorization.

261011331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4143050 (or 4143047 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 261011331 is about 16155.8451032436. The cubic root of 261011331 is about 639.0769008231.

Adding to 261011331 its reverse (133110162), we get a palindrome (394121493).

The spelling of 261011331 in words is "two hundred sixty-one million, eleven thousand, three hundred thirty-one".