13691531 has 16 divisors (see below), whose sum is σ = 16128000. Its totient is φ = 11617704.

The previous prime is 13691527. The next prime is 13691537. The reversal of 13691531 is 13519631.

13691531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 13691531 - 2² = 13691527 is a prime.

It is a super-2 number, since 2×13691531² = 374916042247922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 13691494 and 13691503.

It is not an unprimeable number, because it can be changed into a prime (13691537) 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, 61286 + ... + 61508.

It is an arithmetic number, because the mean of its divisors is an integer number (1008000).

Almost surely, 2^13691531 is an apocalyptic number.

13691531 is a deficient number, since it is larger than the sum of its proper divisors (2436469).

13691531 is an equidigital number, since it uses as much as digits as its factorization.

13691531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423 (or 409 counting only the distinct ones).

The product of its digits is 2430, while the sum is 29.

The square root of 13691531 is about 3700.2068861079. The cubic root of 13691531 is about 239.2309352037.

The spelling of 13691531 in words is "thirteen million, six hundred ninety-one thousand, five hundred thirty-one".