13506991 has 4 divisors (see below), whose sum is σ = 13526152. Its totient is φ = 13487832.

The previous prime is 13506973. The next prime is 13507009. The reversal of 13506991 is 19960531.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (13506973) and next prime (13507009).

It is a cyclic number.

It is not a de Polignac number, because 13506991 - 2⁷ = 13506863 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 (13506901) 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, 8481 + ... + 9946.

It is an arithmetic number, because the mean of its divisors is an integer number (3381538).

Almost surely, 2^13506991 is an apocalyptic number.

13506991 is a deficient number, since it is larger than the sum of its proper divisors (19161).

13506991 is an equidigital number, since it uses as much as digits as its factorization.

13506991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19160.

The product of its (nonzero) digits is 7290, while the sum is 34.

The square root of 13506991 is about 3675.1858456410. The cubic root of 13506991 is about 238.1512526311.

The spelling of 13506991 in words is "thirteen million, five hundred six thousand, nine hundred ninety-one".