13878457 has 2 divisors, whose sum is σ = 13878458. Its totient is φ = 13878456.

The previous prime is 13878439. The next prime is 13878461. The reversal of 13878457 is 75487831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7268416 + 6610041 = 2696^2 + 2571^2 .

It is an emirp because it is prime and its reverse (75487831) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13878457 is a prime.

It is a super-2 number, since 2×13878457² = 385223137401698, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13878427) 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, 6939228 + 6939229.

It is an arithmetic number, because the mean of its divisors is an integer number (6939229).

Almost surely, 2^13878457 is an apocalyptic number.

It is an amenable number.

13878457 is a deficient number, since it is larger than the sum of its proper divisors (1).

13878457 is an equidigital number, since it uses as much as digits as its factorization.

13878457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 188160, while the sum is 43.

The square root of 13878457 is about 3725.3801148339. The cubic root of 13878457 is about 240.3147317618.

The spelling of 13878457 in words is "thirteen million, eight hundred seventy-eight thousand, four hundred fifty-seven".