821881 has 8 divisors (see below), whose sum is σ = 856520. Its totient is φ = 787968.

The previous prime is 821879. The next prime is 821897. The reversal of 821881 is 188128.

821881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 467856 + 354025 = 684^2 + 595^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 821881 - 2¹ = 821879 is a prime.

It is a super-2 number, since 2×821881² = 1350976756322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3475 + ... + 3703.

It is an arithmetic number, because the mean of its divisors is an integer number (107065).

2⁸²¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

821881 is a deficient number, since it is larger than the sum of its proper divisors (34639).

821881 is a wasteful number, since it uses less digits than its factorization.

821881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363.

The product of its digits is 1024, while the sum is 28.

The square root of 821881 is about 906.5765273820. The cubic root of 821881 is about 93.6705305808.

The spelling of 821881 in words is "eight hundred twenty-one thousand, eight hundred eighty-one".