78521400 has 240 divisors, whose sum is σ = 282225240. Its totient is φ = 20217600.

The previous prime is 78521383. The next prime is 78521411. The reversal of 78521400 is 412587.

It is a super-2 number, since 2×78521400² = 12331220515920000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

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 59 ways as a sum of consecutive naturals, for example, 599335 + ... + 599465.

Almost surely, 2^78521400 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 78521400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141112620).

78521400 is an abundant number, since it is smaller than the sum of its proper divisors (203703840).

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

78521400 is a wasteful number, since it uses less digits than its factorization.

78521400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 78521400 is about 8861.2301629063. The cubic root of 78521400 is about 428.2157906799.

Adding to 78521400 its reverse (412587), we get a palindrome (78933987).

The spelling of 78521400 in words is "seventy-eight million, five hundred twenty-one thousand, four hundred".