881721 has 9 divisors (see below), whose sum is σ = 1277679. Its totient is φ = 585936.

The previous prime is 881711. The next prime is 881729. The reversal of 881721 is 127188.

The square root of 881721 is 939.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 5625 + 876096 = 75^2 + 936^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 881721 - 2¹¹ = 879673 is a prime.

881721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (881729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2661 + ... + 2973.

2⁸⁸¹⁷²¹ is an apocalyptic number.

881721 is the 939-th square number.

881721 is the 470-th centered octagonal number.

It is an amenable number.

881721 is a deficient number, since it is larger than the sum of its proper divisors (395958).

881721 is an equidigital number, since it uses as much as digits as its factorization.

881721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632 (or 316 counting only the distinct ones).

The product of its digits is 896, while the sum is 27.

The cubic root of 881721 is about 95.8908264130.

The spelling of 881721 in words is "eight hundred eighty-one thousand, seven hundred twenty-one".