78407557 has 2 divisors, whose sum is σ = 78407558. Its totient is φ = 78407556.

The previous prime is 78407543. The next prime is 78407569. The reversal of 78407557 is 75570487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50253921 + 28153636 = 7089^2 + 5306^2 .

It is a cyclic number.

It is not a de Polignac number, because 78407557 - 2¹⁹ = 77883269 is a prime.

It is a super-2 number, since 2×78407557² = 12295489989416498, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78407507) 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, 39203778 + 39203779.

It is an arithmetic number, because the mean of its divisors is an integer number (39203779).

Almost surely, 2^78407557 is an apocalyptic number.

It is an amenable number.

78407557 is a deficient number, since it is larger than the sum of its proper divisors (1).

78407557 is an equidigital number, since it uses as much as digits as its factorization.

78407557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 274400, while the sum is 43.

The square root of 78407557 is about 8854.8041762650. The cubic root of 78407557 is about 428.0087433070.

The spelling of 78407557 in words is "seventy-eight million, four hundred seven thousand, five hundred fifty-seven".