78215840 has 48 divisors (see below), whose sum is σ = 185885280. Its totient is φ = 31100160.

The previous prime is 78215833. The next prime is 78215843. The reversal of 78215840 is 4851287.

It is a super-2 number, since 2×78215840² = 12235435253811200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78215840.

It is not an unprimeable number, because it can be changed into a prime (78215843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27275 + ... + 30005.

It is an arithmetic number, because the mean of its divisors is an integer number (3872610).

Almost surely, 2^78215840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78215840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92942640).

78215840 is an abundant number, since it is smaller than the sum of its proper divisors (107669440).

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

78215840 is a wasteful number, since it uses less digits than its factorization.

78215840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2925 (or 2917 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 78215840 is about 8843.9719583454. The cubic root of 78215840 is about 427.6596123212.

The spelling of 78215840 in words is "seventy-eight million, two hundred fifteen thousand, eight hundred forty".