78990 has 16 divisors (see below), whose sum is σ = 189648. Its totient is φ = 21056.

The previous prime is 78989. The next prime is 79031. The reversal of 78990 is 9987.

78990 is nontrivially palindromic in base 14.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1287 + ... + 1346.

It is an arithmetic number, because the mean of its divisors is an integer number (11853).

2⁷⁸⁹⁹⁰ is an apocalyptic number.

78990 is an abundant number, since it is smaller than the sum of its proper divisors (110658).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94824).

78990 is a wasteful number, since it uses less digits than its factorization.

78990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2643.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 78990 is about 281.0515966864. The cubic root of 78990 is about 42.9065937127.

The spelling of 78990 in words is "seventy-eight thousand, nine hundred ninety".