78009912 has 128 divisors (see below), whose sum is σ = 228729600. Its totient is φ = 24603264.

The previous prime is 78009881. The next prime is 78009931. The reversal of 78009912 is 21990087.

It is a happy number.

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 polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 343543 + ... + 343769.

It is an arithmetic number, because the mean of its divisors is an integer number (1786950).

Almost surely, 2^78009912 is an apocalyptic number.

78009912 is a gapful number since it is divisible by the number (72) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78009912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114364800).

78009912 is an abundant number, since it is smaller than the sum of its proper divisors (150719688).

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

78009912 is a wasteful number, since it uses less digits than its factorization.

78009912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 78009912 is about 8832.3220049996. The cubic root of 78009912 is about 427.2839659472.

Adding to 78009912 its reverse (21990087), we get a palindrome (99999999).

The spelling of 78009912 in words is "seventy-eight million, nine thousand, nine hundred twelve".