13147991 has 4 divisors (see below), whose sum is σ = 13601400. Its totient is φ = 12694584.

The previous prime is 13147949. The next prime is 13147997. The reversal of 13147991 is 19974131.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19974131 = 3631 ⋅5501.

It is a cyclic number.

It is not a de Polignac number, because 13147991 - 2¹⁴ = 13131607 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 (13147997) 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, 226661 + ... + 226718.

It is an arithmetic number, because the mean of its divisors is an integer number (3400350).

Almost surely, 2^13147991 is an apocalyptic number.

13147991 is a deficient number, since it is larger than the sum of its proper divisors (453409).

13147991 is an equidigital number, since it uses as much as digits as its factorization.

13147991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453408.

The product of its digits is 6804, while the sum is 35.

The square root of 13147991 is about 3626.0158576598. The cubic root of 13147991 is about 236.0223513734.

The spelling of 13147991 in words is "thirteen million, one hundred forty-seven thousand, nine hundred ninety-one".