821242188 has 144 divisors (see below), whose sum is σ = 2391348960. Its totient is φ = 235395072.

The previous prime is 821242159. The next prime is 821242199. The reversal of 821242188 is 881242128.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 866731 + ... + 867677.

It is an arithmetic number, because the mean of its divisors is an integer number (16606590).

Almost surely, 2^821242188 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 821242188, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1195674480).

821242188 is an abundant number, since it is smaller than the sum of its proper divisors (1570106772).

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

821242188 is a wasteful number, since it uses less digits than its factorization.

821242188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1096 (or 1091 counting only the distinct ones).

The product of its digits is 16384, while the sum is 36.

The square root of 821242188 is about 28657.3234619006. The cubic root of 821242188 is about 936.4625562747.

The spelling of 821242188 in words is "eight hundred twenty-one million, two hundred forty-two thousand, one hundred eighty-eight".