78845557 has 24 divisors (see below), whose sum is σ = 95139384. Its totient is φ = 65100672.

The previous prime is 78845551. The next prime is 78845561. The reversal of 78845557 is 75554887.

It can be written as a sum of positive squares in 4 ways, for example, as 8520561 + 70324996 = 2919^2 + 8386^2 .

It is a de Polignac number, because none of the positive numbers 2^k-78845557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78845557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78845551) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 284503 + ... + 284779.

It is an arithmetic number, because the mean of its divisors is an integer number (3964141).

Almost surely, 2^78845557 is an apocalyptic number.

It is an amenable number.

78845557 is a deficient number, since it is larger than the sum of its proper divisors (16293827).

78845557 is a wasteful number, since it uses less digits than its factorization.

78845557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 485 (or 478 counting only the distinct ones).

The product of its digits is 1568000, while the sum is 49.

The square root of 78845557 is about 8879.5020693730. The cubic root of 78845557 is about 428.8042441434.

The spelling of 78845557 in words is "seventy-eight million, eight hundred forty-five thousand, five hundred fifty-seven".