78215870 has 32 divisors (see below), whose sum is σ = 148599360. Its totient is φ = 29582080.

The previous prime is 78215843. The next prime is 78215873. The reversal of 78215870 is 7851287.

It is a super-2 number, since 2×78215870² = 12235444639713800, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78215873) 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, 18560 + ... + 22380.

It is an arithmetic number, because the mean of its divisors is an integer number (4643730).

Almost surely, 2^78215870 is an apocalyptic number.

78215870 is a deficient number, since it is larger than the sum of its proper divisors (70383490).

78215870 is a wasteful number, since it uses less digits than its factorization.

78215870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3940.

The product of its (nonzero) digits is 31360, while the sum is 38.

The square root of 78215870 is about 8843.9736544158. The cubic root of 78215870 is about 427.6596669981.

The spelling of 78215870 in words is "seventy-eight million, two hundred fifteen thousand, eight hundred seventy".