13978366 has 4 divisors (see below), whose sum is σ = 20967552. Its totient is φ = 6989182.

The previous prime is 13978337. The next prime is 13978421. The reversal of 13978366 is 66387931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66387931 = 29 ⋅2289239.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3494590 + ... + 3494593.

It is an arithmetic number, because the mean of its divisors is an integer number (5241888).

Almost surely, 2^13978366 is an apocalyptic number.

13978366 is a deficient number, since it is larger than the sum of its proper divisors (6989186).

13978366 is an equidigital number, since it uses as much as digits as its factorization.

13978366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6989185.

The product of its digits is 163296, while the sum is 43.

The square root of 13978366 is about 3738.7653042147. The cubic root of 13978366 is about 240.8900171356.

The spelling of 13978366 in words is "thirteen million, nine hundred seventy-eight thousand, three hundred sixty-six".