78215228 has 36 divisors (see below), whose sum is σ = 169399440. Its totient is φ = 30940416.

The previous prime is 78215219. The next prime is 78215261. The reversal of 78215228 is 82251287.

It is a super-2 number, since 2×78215228² = 12235243782183968, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3533 + ... + 12996.

It is an arithmetic number, because the mean of its divisors is an integer number (4705540).

Almost surely, 2^78215228 is an apocalyptic number.

It is an amenable number.

78215228 is an abundant number, since it is smaller than the sum of its proper divisors (91184212).

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

78215228 is a wasteful number, since it uses less digits than its factorization.

78215228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16566 (or 16551 counting only the distinct ones).

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

The square root of 78215228 is about 8843.9373584394. The cubic root of 78215228 is about 427.6584969105.

The spelling of 78215228 in words is "seventy-eight million, two hundred fifteen thousand, two hundred twenty-eight".