78391800 has 144 divisors (see below), whose sum is σ = 273185640. Its totient is φ = 20891520.

The previous prime is 78391799. The next prime is 78391813. The reversal of 78391800 is 819387.

It is a super-2 number, since 2×78391800² = 12290548614480000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 47794 + ... + 49406.

Almost surely, 2^78391800 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 78391800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136592820).

78391800 is an abundant number, since it is smaller than the sum of its proper divisors (194793840).

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

78391800 is a wasteful number, since it uses less digits than its factorization.

78391800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1644 (or 1623 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 78391800 is about 8853.9143885628. The cubic root of 78391800 is about 427.9800701117.

The spelling of 78391800 in words is "seventy-eight million, three hundred ninety-one thousand, eight hundred".