31661879818321 has 27 divisors (see below), whose sum is σ = 32418022528251. Its totient is φ = 30923221218624.

The previous prime is 31661879818277. The next prime is 31661879818351. The reversal of 31661879818321 is 12381897816613.

The square root of 31661879818321 is 5626889.

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., 8537937900625 + 23123941917696 = 2921975^2 + 4808736^2 .

It is not a de Polignac number, because 31661879818321 - 2⁷ = 31661879818193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31661879818351) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 93952165465 + ... + 93952165801.

Almost surely, 2^{31661879818321} is an apocalyptic number.

31661879818321 is the 5626889-th square number.

31661879818321 is the 2813445-th centered octagonal number.

It is an amenable number.

31661879818321 is a deficient number, since it is larger than the sum of its proper divisors (756142709930).

31661879818321 is an frugal number, since it uses more digits than its factorization.

31661879818321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1358 (or 679 counting only the distinct ones).

The product of its digits is 20901888, while the sum is 64.

The spelling of 31661879818321 in words is "thirty-one trillion, six hundred sixty-one billion, eight hundred seventy-nine million, eight hundred eighteen thousand, three hundred twenty-one".