78427440 has 600 divisors, whose sum is σ = 359195760. Its totient is φ = 15676416.

The previous prime is 78427429. The next prime is 78427451. The reversal of 78427440 is 4472487.

It is an interprime number because it is at equal distance from previous prime (78427429) and next prime (78427451).

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

It is a junction number, because it is equal to n+sod(n) for n = 78427395 and 78427404.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 4127751 + ... + 4127769.

Almost surely, 2^78427440 is an apocalyptic number.

78427440 is a gapful number since it is divisible by the number (70) 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 78427440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179597880).

78427440 is an abundant number, since it is smaller than the sum of its proper divisors (280768320).

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

78427440 is a wasteful number, since it uses less digits than its factorization.

78427440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71 (or 49 counting only the distinct ones).

The product of its (nonzero) digits is 50176, while the sum is 36.

The square root of 78427440 is about 8855.9268289660. The cubic root of 78427440 is about 428.0449191508.

It can be divided in two parts, 784 and 27440, that added together give a square (28224 = 168²).

The spelling of 78427440 in words is "seventy-eight million, four hundred twenty-seven thousand, four hundred forty".