897721 has 4 divisors (see below), whose sum is σ = 979344. Its totient is φ = 816100.

The previous prime is 897709. The next prime is 897727. The reversal of 897721 is 127798.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 897721 - 2⁷ = 897593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (897727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40795 + ... + 40816.

It is an arithmetic number, because the mean of its divisors is an integer number (244836).

2⁸⁹⁷⁷²¹ is an apocalyptic number.

It is an amenable number.

897721 is a deficient number, since it is larger than the sum of its proper divisors (81623).

897721 is a wasteful number, since it uses less digits than its factorization.

897721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81622.

The product of its digits is 7056, while the sum is 34.

The square root of 897721 is about 947.4813982343. The cubic root of 897721 is about 96.4673751204.

It can be divided in two parts, 8977 and 21, that added together give a palindrome (8998).

The spelling of 897721 in words is "eight hundred ninety-seven thousand, seven hundred twenty-one".