78221888 has 28 divisors (see below), whose sum is σ = 156659580. Its totient is φ = 38748672.

The previous prime is 78221881. The next prime is 78221893. The reversal of 78221888 is 88812287.

It can be written as a sum of positive squares in 2 ways, for example, as 24522304 + 53699584 = 4952^2 + 7328^2 .

It is a super-2 number, since 2×78221888² = 12237327524569088, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78221881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1370 + ... + 12582.

It is an arithmetic number, because the mean of its divisors is an integer number (5594985).

Almost surely, 2^78221888 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 78221888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78329790).

78221888 is an abundant number, since it is smaller than the sum of its proper divisors (78437692).

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

78221888 is a wasteful number, since it uses less digits than its factorization.

78221888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11334 (or 11324 counting only the distinct ones).

The product of its digits is 114688, while the sum is 44.

The square root of 78221888 is about 8844.3138795500. The cubic root of 78221888 is about 427.6706348910.

The spelling of 78221888 in words is "seventy-eight million, two hundred twenty-one thousand, eight hundred eighty-eight".