78231636 has 72 divisors (see below), whose sum is σ = 235952640. Its totient is φ = 22350384.

The previous prime is 78231617. The next prime is 78231661. The reversal of 78231636 is 63613287.

It is a happy number.

It is a super-2 number, since 2×78231636² = 12240377742472992, which contains 22 as substring.

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

It is a self number, because there is not a number n which added to its sum of digits gives 78231636.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2100 + ... + 12683.

It is an arithmetic number, because the mean of its divisors is an integer number (3277120).

Almost surely, 2^78231636 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 78231636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117976320).

78231636 is an abundant number, since it is smaller than the sum of its proper divisors (157721004).

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

78231636 is a wasteful number, since it uses less digits than its factorization.

78231636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14810 (or 14795 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 78231636 is about 8844.8649509193. The cubic root of 78231636 is about 427.6883995700.

The spelling of 78231636 in words is "seventy-eight million, two hundred thirty-one thousand, six hundred thirty-six".