821116881 has 48 divisors (see below), whose sum is σ = 1385551440. Its totient is φ = 463933440.

The previous prime is 821116861. The next prime is 821116897. The reversal of 821116881 is 188611128.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 160883856 + 660233025 = 12684^2 + 25695^2 .

It is not a de Polignac number, because 821116881 - 2¹⁸ = 820854737 is a prime.

It is a super-2 number, since 2×821116881² = 1348465864526336322, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (821116801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 76515 + ... + 86583.

It is an arithmetic number, because the mean of its divisors is an integer number (28865655).

Almost surely, 2^821116881 is an apocalyptic number.

It is an amenable number.

821116881 is a deficient number, since it is larger than the sum of its proper divisors (564434559).

821116881 is a wasteful number, since it uses less digits than its factorization.

821116881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10146 (or 10143 counting only the distinct ones).

The product of its digits is 6144, while the sum is 36.

The square root of 821116881 is about 28655.1370787159. The cubic root of 821116881 is about 936.4149246568.

The spelling of 821116881 in words is "eight hundred twenty-one million, one hundred sixteen thousand, eight hundred eighty-one".