99821178 has 72 divisors (see below), whose sum is σ = 237544320. Its totient is φ = 30257280.

The previous prime is 99821177. The next prime is 99821191. The reversal of 99821178 is 87112899.

Its product of digits (72576) is a multiple of the sum of its prime divisors (672).

It is not an unprimeable number, because it can be changed into a prime (99821171) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 160953 + ... + 161571.

Almost surely, 2^99821178 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99821178, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (118772160).

99821178 is an abundant number, since it is smaller than the sum of its proper divisors (137723142).

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

99821178 is a wasteful number, since it uses less digits than its factorization.

99821178 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692 (or 672 counting only the distinct ones).

The product of its digits is 72576, while the sum is 45.

The square root of 99821178 is about 9991.0548992586. The cubic root of 99821178 is about 463.8820455472.

It can be divided in two parts, 99821 and 178, that added together give a palindrome (99999).

The spelling of 99821178 in words is "ninety-nine million, eight hundred twenty-one thousand, one hundred seventy-eight".