78638688 has 84 divisors (see below), whose sum is σ = 232192548. Its totient is φ = 26205120.

The previous prime is 78638669. The next prime is 78638689. The reversal of 78638688 is 88683687.

It is a happy number.

It is a super-2 number, since 2×78638688² = 12368086500722688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78638689) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 21643 + ... + 25013.

It is an arithmetic number, because the mean of its divisors is an integer number (2764197).

Almost surely, 2^78638688 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 78638688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116096274).

78638688 is an abundant number, since it is smaller than the sum of its proper divisors (153553860).

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

78638688 is an equidigital number, since it uses as much as digits as its factorization.

78638688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3399 (or 3376 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 54.

The square root of 78638688 is about 8867.8457361413. The cubic root of 78638688 is about 428.4288943155.

The spelling of 78638688 in words is "seventy-eight million, six hundred thirty-eight thousand, six hundred eighty-eight".