13778657 has 2 divisors, whose sum is σ = 13778658. Its totient is φ = 13778656.

The previous prime is 13778641. The next prime is 13778659. The reversal of 13778657 is 75687731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10764961 + 3013696 = 3281^2 + 1736^2 .

It is a cyclic number.

It is not a de Polignac number, because 13778657 - 2⁴ = 13778641 is a prime.

Together with 13778659, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (13778659) by changing a digit.

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 as a sum of consecutive naturals, namely, 6889328 + 6889329.

It is an arithmetic number, because the mean of its divisors is an integer number (6889329).

Almost surely, 2^13778657 is an apocalyptic number.

It is an amenable number.

13778657 is a deficient number, since it is larger than the sum of its proper divisors (1).

13778657 is an equidigital number, since it uses as much as digits as its factorization.

13778657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 246960, while the sum is 44.

The square root of 13778657 is about 3711.9613413935. The cubic root of 13778657 is about 239.7373109615.

The spelling of 13778657 in words is "thirteen million, seven hundred seventy-eight thousand, six hundred fifty-seven".