78557987 has 2 divisors, whose sum is σ = 78557988. Its totient is φ = 78557986.

The previous prime is 78557959. The next prime is 78558017. The reversal of 78557987 is 78975587.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78557987 is a prime.

It is not a weakly prime, because it can be changed into another prime (78557957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39278993 + 39278994.

It is an arithmetic number, because the mean of its divisors is an integer number (39278994).

Almost surely, 2^78557987 is an apocalyptic number.

78557987 is a deficient number, since it is larger than the sum of its proper divisors (1).

78557987 is an equidigital number, since it uses as much as digits as its factorization.

78557987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4939200, while the sum is 56.

The square root of 78557987 is about 8863.2943649639. The cubic root of 78557987 is about 428.2822893176.

The spelling of 78557987 in words is "seventy-eight million, five hundred fifty-seven thousand, nine hundred eighty-seven".