87221988 has 96 divisors (see below), whose sum is σ = 260977920. Its totient is φ = 24675840.

The previous prime is 87221983. The next prime is 87222011. The reversal of 87221988 is 88912278.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (87221983) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 84918 + ... + 85938.

It is an arithmetic number, because the mean of its divisors is an integer number (2718520).

Almost surely, 2^87221988 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 87221988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130488960).

87221988 is an abundant number, since it is smaller than the sum of its proper divisors (173755932).

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

87221988 is a wasteful number, since it uses less digits than its factorization.

87221988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1154 (or 1146 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 87221988 is about 9339.2712777818. The cubic root of 87221988 is about 443.4813154145.

It can be divided in two parts, 87221 and 988, that added together give a square (88209 = 297²).

The spelling of 87221988 in words is "eighty-seven million, two hundred twenty-one thousand, nine hundred eighty-eight".