78308440 has 64 divisors (see below), whose sum is σ = 202824000. Its totient is φ = 26654208.

The previous prime is 78308437. The next prime is 78308453. The reversal of 78308440 is 4480387.

It is a super-2 number, since 2×78308440² = 12264423550467200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78308396 and 78308405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40782 + ... + 42658.

It is an arithmetic number, because the mean of its divisors is an integer number (3169125).

Almost surely, 2^78308440 is an apocalyptic number.

78308440 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 78308440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101412000).

78308440 is an abundant number, since it is smaller than the sum of its proper divisors (124515560).

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

78308440 is a wasteful number, since it uses less digits than its factorization.

78308440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2044 (or 2040 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 78308440 is about 8849.2056140650. The cubic root of 78308440 is about 427.8283149879.

The spelling of 78308440 in words is "seventy-eight million, three hundred eight thousand, four hundred forty".