13091531 has 4 divisors (see below), whose sum is σ = 13660752. Its totient is φ = 12522312.

The previous prime is 13091527. The next prime is 13091537. The reversal of 13091531 is 13519031.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13519031 = 443 ⋅30517.

It is a cyclic number.

It is not a de Polignac number, because 13091531 - 2² = 13091527 is a prime.

It is a super-2 number, since 2×13091531² = 342776367847922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 569197 = 13091531 / (1 + 3 + 0 + 9 + 1 + 5 + 3 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 13091497 and 13091506.

It is not an unprimeable number, because it can be changed into a prime (13091537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 284576 + ... + 284621.

It is an arithmetic number, because the mean of its divisors is an integer number (3415188).

Almost surely, 2^13091531 is an apocalyptic number.

13091531 is a deficient number, since it is larger than the sum of its proper divisors (569221).

13091531 is an equidigital number, since it uses as much as digits as its factorization.

13091531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 569220.

The product of its (nonzero) digits is 405, while the sum is 23.

The square root of 13091531 is about 3618.2220772086. Note that the first 3 decimals coincide. The cubic root of 13091531 is about 235.6840248529.

The spelling of 13091531 in words is "thirteen million, ninety-one thousand, five hundred thirty-one".