821889138 has 32 divisors (see below), whose sum is σ = 1879787520. Its totient is φ = 234677520.

The previous prime is 821889127. The next prime is 821889151. The reversal of 821889138 is 831988128.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73353 + ... + 83811.

It is an arithmetic number, because the mean of its divisors is an integer number (58743360).

Almost surely, 2^821889138 is an apocalyptic number.

821889138 is an abundant number, since it is smaller than the sum of its proper divisors (1057898382).

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

821889138 is a wasteful number, since it uses less digits than its factorization.

821889138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12342.

The product of its digits is 221184, while the sum is 48.

The square root of 821889138 is about 28668.6089303266. The cubic root of 821889138 is about 936.7083974490.

The spelling of 821889138 in words is "eight hundred twenty-one million, eight hundred eighty-nine thousand, one hundred thirty-eight".