78857220 has 192 divisors, whose sum is σ = 265870080. Its totient is φ = 17252352.

The previous prime is 78857173. The next prime is 78857231. The reversal of 78857220 is 2275887.

It is a super-2 number, since 2×78857220² = 12436922292256800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 251784 + ... + 252096.

It is an arithmetic number, because the mean of its divisors is an integer number (1384740).

Almost surely, 2^78857220 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 78857220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (132935040).

78857220 is an abundant number, since it is smaller than the sum of its proper divisors (187012860).

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

78857220 is a wasteful number, since it uses less digits than its factorization.

78857220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374 (or 372 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 39.

The square root of 78857220 is about 8880.1587823642. The cubic root of 78857220 is about 428.8253863084.

The spelling of 78857220 in words is "seventy-eight million, eight hundred fifty-seven thousand, two hundred twenty".