78157091 has 2 divisors, whose sum is σ = 78157092. Its totient is φ = 78157090.

The previous prime is 78157073. The next prime is 78157103. The reversal of 78157091 is 19075187.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78157091 - 2²⁶ = 11048227 is a prime.

It is a super-2 number, since 2×78157091² = 12217061747164562, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78157031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39078545 + 39078546.

It is an arithmetic number, because the mean of its divisors is an integer number (39078546).

Almost surely, 2^78157091 is an apocalyptic number.

78157091 is a deficient number, since it is larger than the sum of its proper divisors (1).

78157091 is an equidigital number, since it uses as much as digits as its factorization.

78157091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17640, while the sum is 38.

The square root of 78157091 is about 8840.6499195478. The cubic root of 78157091 is about 427.5525118172.

The spelling of 78157091 in words is "seventy-eight million, one hundred fifty-seven thousand, ninety-one".