13991647 has 4 divisors (see below), whose sum is σ = 14000320. Its totient is φ = 13982976.

The previous prime is 13991639. The next prime is 13991651. The reversal of 13991647 is 74619931.

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.

It is a cyclic number.

It is not a de Polignac number, because 13991647 - 2³ = 13991639 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 (13991687) 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, 1122 + ... + 5407.

It is an arithmetic number, because the mean of its divisors is an integer number (3500080).

It is a Poulet number, since it divides 2^13991646-1.

Almost surely, 2^13991647 is an apocalyptic number.

13991647 is a deficient number, since it is larger than the sum of its proper divisors (8673).

13991647 is an equidigital number, since it uses as much as digits as its factorization.

13991647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8672.

The product of its digits is 40824, while the sum is 40.

The square root of 13991647 is about 3740.5410036517. The cubic root of 13991647 is about 240.9662837425.

The spelling of 13991647 in words is "thirteen million, nine hundred ninety-one thousand, six hundred forty-seven".