13978766 has 4 divisors (see below), whose sum is σ = 20968152. Its totient is φ = 6989382.

The previous prime is 13978759. The next prime is 13978793. The reversal of 13978766 is 66787931.

13978766 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.

It is a self number, because there is not a number n which added to its sum of digits gives 13978766.

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, 3494690 + ... + 3494693.

It is an arithmetic number, because the mean of its divisors is an integer number (5242038).

Almost surely, 2^13978766 is an apocalyptic number.

13978766 is a deficient number, since it is larger than the sum of its proper divisors (6989386).

13978766 is an equidigital number, since it uses as much as digits as its factorization.

13978766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6989385.

The product of its digits is 381024, while the sum is 47.

The square root of 13978766 is about 3738.8187974279. The cubic root of 13978766 is about 240.8923148550.

The spelling of 13978766 in words is "thirteen million, nine hundred seventy-eight thousand, seven hundred sixty-six".