13887778 has 4 divisors (see below), whose sum is σ = 20831670. Its totient is φ = 6943888.

The previous prime is 13887761. The next prime is 13887817. The reversal of 13887778 is 87778831.

13887778 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 can be written as a sum of positive squares in only one way, i.e., 11108889 + 2778889 = 3333^2 + 1667^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3471943 + ... + 3471946.

Almost surely, 2^13887778 is an apocalyptic number.

13887778 is a deficient number, since it is larger than the sum of its proper divisors (6943892).

13887778 is an equidigital number, since it uses as much as digits as its factorization.

13887778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6943891.

The product of its digits is 526848, while the sum is 49.

The square root of 13887778 is about 3726.6309181350. The cubic root of 13887778 is about 240.3685194976.

The spelling of 13887778 in words is "thirteen million, eight hundred eighty-seven thousand, seven hundred seventy-eight".