78721400 has 48 divisors (see below), whose sum is σ = 188946240. Its totient is φ = 30470400.

The previous prime is 78721393. The next prime is 78721421. The reversal of 78721400 is 412787.

It is a plaindrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 149 + ... + 12548.

It is an arithmetic number, because the mean of its divisors is an integer number (3936380).

Almost surely, 2^78721400 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 78721400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94473120).

78721400 is an abundant number, since it is smaller than the sum of its proper divisors (110224840).

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

78721400 is a wasteful number, since it uses less digits than its factorization.

78721400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12744 (or 12735 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 78721400 is about 8872.5081008698. The cubic root of 78721400 is about 428.5790485418.

The spelling of 78721400 in words is "seventy-eight million, seven hundred twenty-one thousand, four hundred".