78312400 has 30 divisors (see below), whose sum is σ = 188146502. Its totient is φ = 31324800.

The previous prime is 78312389. The next prime is 78312431. The reversal of 78312400 is 421387.

It can be written as a sum of positive squares in 3 ways, for example, as 1784896 + 76527504 = 1336^2 + 8748^2 .

It is a super-2 number, since 2×78312400² = 12265663987520000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 97491 + ... + 98290.

Almost surely, 2^78312400 is an apocalyptic number.

It is an amenable number.

78312400 is an abundant number, since it is smaller than the sum of its proper divisors (109834102).

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

78312400 is a wasteful number, since it uses less digits than its factorization.

78312400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195799 (or 195788 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 78312400 is about 8849.4293601339. The cubic root of 78312400 is about 427.8355265203.

Adding to 78312400 its reverse (421387), we get a palindrome (78733787).

The spelling of 78312400 in words is "seventy-eight million, three hundred twelve thousand, four hundred".