78819887 has 4 divisors (see below), whose sum is σ = 81362496. Its totient is φ = 76277280.

The previous prime is 78819877. The next prime is 78819901. The reversal of 78819887 is 78891887.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78891887 = 1447 ⋅54521.

It is a cyclic number.

It is not a de Polignac number, because 78819887 - 2¹⁰ = 78818863 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 (78819857) 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, 1271258 + ... + 1271319.

It is an arithmetic number, because the mean of its divisors is an integer number (20340624).

Almost surely, 2^78819887 is an apocalyptic number.

78819887 is a deficient number, since it is larger than the sum of its proper divisors (2542609).

78819887 is a wasteful number, since it uses less digits than its factorization.

78819887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2542608.

The product of its digits is 1806336, while the sum is 56.

The square root of 78819887 is about 8878.0564877680. The cubic root of 78819887 is about 428.7577033695.

The spelling of 78819887 in words is "seventy-eight million, eight hundred nineteen thousand, eight hundred eighty-seven".