78289920 has 132 divisors (see below), whose sum is σ = 271432200. Its totient is φ = 20865024.

The previous prime is 78289909. The next prime is 78289927. The reversal of 78289920 is 2998287.

It is a super-2 number, since 2×78289920² = 12258623147212800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78289927) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45231 + ... + 46929.

Almost surely, 2^78289920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78289920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135716100).

78289920 is an abundant number, since it is smaller than the sum of its proper divisors (193142280).

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

78289920 is a wasteful number, since it uses less digits than its factorization.

78289920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1730 (or 1709 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 78289920 is about 8848.1591305763. The cubic root of 78289920 is about 427.7945850983.

The spelling of 78289920 in words is "seventy-eight million, two hundred eighty-nine thousand, nine hundred twenty".