13978217 has 4 divisors (see below), whose sum is σ = 15248976. Its totient is φ = 12707460.

The previous prime is 13978207. The next prime is 13978249. The reversal of 13978217 is 71287931.

13978217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13978217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13978207) 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, 635363 + ... + 635384.

It is an arithmetic number, because the mean of its divisors is an integer number (3812244).

Almost surely, 2^13978217 is an apocalyptic number.

It is an amenable number.

13978217 is a deficient number, since it is larger than the sum of its proper divisors (1270759).

13978217 is a wasteful number, since it uses less digits than its factorization.

13978217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1270758.

The product of its digits is 21168, while the sum is 38.

The square root of 13978217 is about 3738.7453777972. The cubic root of 13978217 is about 240.8891612239.

The spelling of 13978217 in words is "thirteen million, nine hundred seventy-eight thousand, two hundred seventeen".