169217872321 has 3 divisors (see below), whose sum is σ = 169218283683. Its totient is φ = 169217460960.

The previous prime is 169217872319. The next prime is 169217872337. The reversal of 169217872321 is 123278712961.

The square root of 169217872321 is 411361.

It is a perfect power (a square), and thus also a powerful number.

169217872321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 136817872321 + 32400000000 = 369889^2 + 180000^2 .

It is not a de Polignac number, because 169217872321 - 2¹ = 169217872319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (169217872301) 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 2 ways as a sum of consecutive naturals, for example, 205681 + ... + 617041.

It is an arithmetic number, because the mean of its divisors is an integer number (56406094561).

Almost surely, 2^169217872321 is an apocalyptic number.

169217872321 is the 411361-st square number.

169217872321 is the 205681-st centered octagonal number.

It is an amenable number.

169217872321 is a deficient number, since it is larger than the sum of its proper divisors (411362).

169217872321 is an frugal number, since it uses more digits than its factorization.

169217872321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 822722 (or 411361 counting only the distinct ones).

The product of its digits is 508032, while the sum is 49.

Multiplying 169217872321 by its sum of digits (49), we get a square (8291675743729 = 2879527²).

The spelling of 169217872321 in words is "one hundred sixty-nine billion, two hundred seventeen million, eight hundred seventy-two thousand, three hundred twenty-one".