78683640 has 128 divisors (see below), whose sum is σ = 275650560. Its totient is φ = 17593344.

The previous prime is 78683629. The next prime is 78683651. The reversal of 78683640 is 4638687.

It is an interprime number because it is at equal distance from previous prime (78683629) and next prime (78683651).

It is a super-2 number, since 2×78683640² = 12382230407299200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 78683592 and 78683601.

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, 38484 + ... + 40476.

It is an arithmetic number, because the mean of its divisors is an integer number (2153520).

Almost surely, 2^78683640 is an apocalyptic number.

78683640 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 78683640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137825280).

78683640 is an abundant number, since it is smaller than the sum of its proper divisors (196966920).

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

78683640 is a wasteful number, since it uses less digits than its factorization.

78683640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2061 (or 2057 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 42.

The square root of 78683640 is about 8870.3799242197. The cubic root of 78683640 is about 428.5105126118.

The spelling of 78683640 in words is "seventy-eight million, six hundred eighty-three thousand, six hundred forty".