997211321 has 4 divisors (see below), whose sum is σ = 998725200. Its totient is φ = 995697444.

The previous prime is 997211297. The next prime is 997211329. The reversal of 997211321 is 123112799.

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 a de Polignac number, because none of the positive numbers 2^k-997211321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (997211329) 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 3 ways as a sum of consecutive naturals, for example, 755951 + ... + 757268.

It is an arithmetic number, because the mean of its divisors is an integer number (249681300).

Almost surely, 2^997211321 is an apocalyptic number.

997211321 is the 16880-th centered heptagonal number.

It is an amenable number.

997211321 is a deficient number, since it is larger than the sum of its proper divisors (1513879).

997211321 is a wasteful number, since it uses less digits than its factorization.

997211321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1513878.

The product of its digits is 6804, while the sum is 35.

The square root of 997211321 is about 31578.6529320046. The cubic root of 997211321 is about 999.0695749110.

The spelling of 997211321 in words is "nine hundred ninety-seven million, two hundred eleven thousand, three hundred twenty-one".