11661531 has 16 divisors (see below), whose sum is σ = 18015744. Its totient is φ = 6571584.

The previous prime is 11661523. The next prime is 11661547. The reversal of 11661531 is 13516611.

It is not a de Polignac number, because 11661531 - 2³ = 11661523 is a prime.

It is a super-2 number, since 2×11661531² = 271982610527922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (11661571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2271 + ... + 5336.

It is an arithmetic number, because the mean of its divisors is an integer number (1125984).

Almost surely, 2^11661531 is an apocalyptic number.

11661531 is a deficient number, since it is larger than the sum of its proper divisors (6354213).

11661531 is an equidigital number, since it uses as much as digits as its factorization.

11661531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7690.

The product of its digits is 540, while the sum is 24.

The square root of 11661531 is about 3414.8983879466. The cubic root of 11661531 is about 226.7697860768.

The spelling of 11661531 in words is "eleven million, six hundred sixty-one thousand, five hundred thirty-one".