78391040 has 144 divisors (see below), whose sum is σ = 231446208. Its totient is φ = 24772608.

The previous prime is 78391009. The next prime is 78391043. The reversal of 78391040 is 4019387.

It is a super-2 number, since 2×78391040² = 12290310304563200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 78390988 and 78391006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78391043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 116144 + ... + 116816.

Almost surely, 2^78391040 is an apocalyptic number.

78391040 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 78391040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115723104).

78391040 is an abundant number, since it is smaller than the sum of its proper divisors (153055168).

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

78391040 is a wasteful number, since it uses less digits than its factorization.

78391040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 714 (or 700 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 78391040 is about 8853.8714695889. The cubic root of 78391040 is about 427.9786870337.

The spelling of 78391040 in words is "seventy-eight million, three hundred ninety-one thousand, forty".