78544813 has 4 divisors (see below), whose sum is σ = 79307488. Its totient is φ = 77782140.

The previous prime is 78544787. The next prime is 78544819. The reversal of 78544813 is 31844587.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31844587 = 17 ⋅1873211.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78544813 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 (78544819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 381183 + ... + 381388.

It is an arithmetic number, because the mean of its divisors is an integer number (19826872).

Almost surely, 2^78544813 is an apocalyptic number.

It is an amenable number.

78544813 is a deficient number, since it is larger than the sum of its proper divisors (762675).

78544813 is a wasteful number, since it uses less digits than its factorization.

78544813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 762674.

The product of its digits is 107520, while the sum is 40.

The square root of 78544813 is about 8862.5511564109. The cubic root of 78544813 is about 428.2583473162.

The spelling of 78544813 in words is "seventy-eight million, five hundred forty-four thousand, eight hundred thirteen".