78749557 has 8 divisors (see below), whose sum is σ = 79665080. Its totient is φ = 77837760.

The previous prime is 78749543. The next prime is 78749563. The reversal of 78749557 is 75594787.

It can be written as a sum of positive squares in 4 ways, for example, as 54552996 + 24196561 = 7386^2 + 4919^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78749557 - 2²³ = 70360949 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78749507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71503 + ... + 72595.

It is an arithmetic number, because the mean of its divisors is an integer number (9958135).

Almost surely, 2^78749557 is an apocalyptic number.

It is an amenable number.

78749557 is a deficient number, since it is larger than the sum of its proper divisors (915523).

78749557 is a wasteful number, since it uses less digits than its factorization.

78749557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1863.

The product of its digits is 2469600, while the sum is 52.

The square root of 78749557 is about 8874.0947143920. The cubic root of 78749557 is about 428.6301403744.

The spelling of 78749557 in words is "seventy-eight million, seven hundred forty-nine thousand, five hundred fifty-seven".