78686790 has 256 divisors, whose sum is σ = 257402880. Its totient is φ = 14929920.

The previous prime is 78686737. The next prime is 78686791. The reversal of 78686790 is 9768687.

It is a happy number.

It is a super-2 number, since 2×78686790² = 12383221841008200, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78686791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1919170 + ... + 1919210.

It is an arithmetic number, because the mean of its divisors is an integer number (1005480).

Almost surely, 2^78686790 is an apocalyptic number.

78686790 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 78686790, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128701440).

78686790 is an abundant number, since it is smaller than the sum of its proper divisors (178716090).

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

78686790 is a wasteful number, since it uses less digits than its factorization.

78686790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127.

The product of its (nonzero) digits is 1016064, while the sum is 51.

The square root of 78686790 is about 8870.5574796627. The cubic root of 78686790 is about 428.5162308276.

The spelling of 78686790 in words is "seventy-eight million, six hundred eighty-six thousand, seven hundred ninety".