997632221 has 16 divisors (see below), whose sum is σ = 1081978560. Its totient is φ = 916634880.

The previous prime is 997632217. The next prime is 997632257. The reversal of 997632221 is 122236799.

It is a cyclic number.

It is not a de Polignac number, because 997632221 - 2² = 997632217 is a prime.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997632271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 234806 + ... + 239016.

It is an arithmetic number, because the mean of its divisors is an integer number (67623660).

Almost surely, 2^997632221 is an apocalyptic number.

It is an amenable number.

997632221 is a deficient number, since it is larger than the sum of its proper divisors (84346339).

997632221 is a wasteful number, since it uses less digits than its factorization.

997632221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4604.

The product of its digits is 81648, while the sum is 41.

The square root of 997632221 is about 31585.3165410765. The cubic root of 997632221 is about 999.2101165818.

The spelling of 997632221 in words is "nine hundred ninety-seven million, six hundred thirty-two thousand, two hundred twenty-one".