997321957633 has 8 divisors (see below), whose sum is σ = 1000065315752. Its totient is φ = 994579762176.

The previous prime is 997321957603. The next prime is 997321957747. The reversal of 997321957633 is 336759123799.

It can be written as a sum of positive squares in 4 ways, for example, as 835438044529 + 161883913104 = 914023^2 + 402348^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 4-Lehmer number, since φ(997321957633) divides (997321957633-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 997321957633 - 2⁵ = 997321957601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (997321957603) 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, 1441441 + ... + 2018017.

It is an arithmetic number, because the mean of its divisors is an integer number (125008164469).

Almost surely, 2^997321957633 is an apocalyptic number.

997321957633 is the 576577-th octagonal number.

It is an amenable number.

997321957633 is a deficient number, since it is larger than the sum of its proper divisors (2743358119).

997321957633 is a wasteful number, since it uses less digits than its factorization.

997321957633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 581331.

The product of its digits is 57868020, while the sum is 64.

The spelling of 997321957633 in words is "nine hundred ninety-seven billion, three hundred twenty-one million, nine hundred fifty-seven thousand, six hundred thirty-three".