13778217 has 6 divisors (see below), whose sum is σ = 19901882. Its totient is φ = 9185472.

The previous prime is 13778213. The next prime is 13778221. The reversal of 13778217 is 71287731.

It is a happy number.

13778217 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (13778213) and next prime (13778221).

It can be written as a sum of positive squares in only one way, i.e., 11634921 + 2143296 = 3411^2 + 1464^2 .

It is not a de Polignac number, because 13778217 - 2² = 13778213 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13778213) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 765448 + ... + 765465.

Almost surely, 2^13778217 is an apocalyptic number.

It is an amenable number.

13778217 is a deficient number, since it is larger than the sum of its proper divisors (6123665).

13778217 is a wasteful number, since it uses less digits than its factorization.

13778217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530919 (or 1530916 counting only the distinct ones).

The product of its digits is 16464, while the sum is 36.

The square root of 13778217 is about 3711.9020730617. The cubic root of 13778217 is about 239.7347590548.

The spelling of 13778217 in words is "thirteen million, seven hundred seventy-eight thousand, two hundred seventeen".