78398137 has 2 divisors, whose sum is σ = 78398138. Its totient is φ = 78398136.

The previous prime is 78398087. The next prime is 78398149. The reversal of 78398137 is 73189387.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71554681 + 6843456 = 8459^2 + 2616^2 .

It is a cyclic number.

It is not a de Polignac number, because 78398137 - 2¹⁹ = 77873849 is a prime.

It is a super-2 number, since 2×78398137² = 12292535770141538, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78398737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39199068 + 39199069.

It is an arithmetic number, because the mean of its divisors is an integer number (39199069).

Almost surely, 2^78398137 is an apocalyptic number.

It is an amenable number.

78398137 is a deficient number, since it is larger than the sum of its proper divisors (1).

78398137 is an equidigital number, since it uses as much as digits as its factorization.

78398137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 46.

The square root of 78398137 is about 8854.2722456450. The cubic root of 78398137 is about 427.9916020858.

The spelling of 78398137 in words is "seventy-eight million, three hundred ninety-eight thousand, one hundred thirty-seven".