821000881 has 8 divisors (see below), whose sum is σ = 852667560. Its totient is φ = 789833088.

The previous prime is 821000879. The next prime is 821000909. The reversal of 821000881 is 188000128.

It can be written as a sum of positive squares in 4 ways, for example, as 243079281 + 577921600 = 15591^2 + 24040^2 .

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 821000881 - 2¹ = 821000879 is a prime.

It is a super-2 number, since 2×821000881² = 1348084893205552322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821000861) 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, 121366 + ... + 127951.

It is an arithmetic number, because the mean of its divisors is an integer number (106583445).

Almost surely, 2^821000881 is an apocalyptic number.

It is an amenable number.

821000881 is a deficient number, since it is larger than the sum of its proper divisors (31666679).

821000881 is a wasteful number, since it uses less digits than its factorization.

821000881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249443.

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

The square root of 821000881 is about 28653.1129373407. The cubic root of 821000881 is about 936.3708264903.

The spelling of 821000881 in words is "eight hundred twenty-one million, eight hundred eighty-one", and thus it is an aban number.