13997778 has 16 divisors (see below), whose sum is σ = 28961280. Its totient is φ = 4504976.

The previous prime is 13997761. The next prime is 13997791. The reversal of 13997778 is 87779931.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 13997778.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40050 + ... + 40397.

It is an arithmetic number, because the mean of its divisors is an integer number (1810080).

Almost surely, 2^13997778 is an apocalyptic number.

13997778 is an abundant number, since it is smaller than the sum of its proper divisors (14963502).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

13997778 is a wasteful number, since it uses less digits than its factorization.

13997778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80481.

The product of its digits is 666792, while the sum is 51.

The square root of 13997778 is about 3741.3604477516. The cubic root of 13997778 is about 241.0014749426.

The spelling of 13997778 in words is "thirteen million, nine hundred ninety-seven thousand, seven hundred seventy-eight".