84875821821 has 18 divisors (see below), whose sum is σ = 142614476862. Its totient is φ = 48500469360.

The previous prime is 84875821819. The next prime is 84875821879. The reversal of 84875821821 is 12812857848.

It is a happy number.

84875821821 is a `hidden beast` number, since 8 + 48 + 7 + 582 + 18 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 67698836100 + 17176985721 = 260190^2 + 131061^2 .

It is not a de Polignac number, because 84875821821 - 2¹ = 84875821819 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84875821801) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 96230650 + ... + 96231531.

Almost surely, 2^84875821821 is an apocalyptic number.

It is an amenable number.

84875821821 is a deficient number, since it is larger than the sum of its proper divisors (57738655041).

84875821821 is a wasteful number, since it uses less digits than its factorization.

84875821821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192462201 (or 192462191 counting only the distinct ones).

The product of its digits is 2293760, while the sum is 54.

The spelling of 84875821821 in words is "eighty-four billion, eight hundred seventy-five million, eight hundred twenty-one thousand, eight hundred twenty-one".