13691551 has 4 divisors (see below), whose sum is σ = 13699504. Its totient is φ = 13683600.

The previous prime is 13691549. The next prime is 13691563. The reversal of 13691551 is 15519631.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 15519631 = 3877 ⋅4003.

It is a cyclic number.

It is not a de Polignac number, because 13691551 - 2¹ = 13691549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13691351) 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, 195 + ... + 5236.

It is an arithmetic number, because the mean of its divisors is an integer number (3424876).

Almost surely, 2^13691551 is an apocalyptic number.

13691551 is a deficient number, since it is larger than the sum of its proper divisors (7953).

13691551 is an equidigital number, since it uses as much as digits as its factorization.

13691551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7952.

The product of its digits is 4050, while the sum is 31.

The square root of 13691551 is about 3700.2095886585. The cubic root of 13691551 is about 239.2310516897.

The spelling of 13691551 in words is "thirteen million, six hundred ninety-one thousand, five hundred fifty-one".