864172892881 has 3 divisors (see below), whose sum is σ = 864173822491. Its totient is φ = 864171963272.

The previous prime is 864172892851. The next prime is 864172892887. The reversal of 864172892881 is 188298271468.

The square root of 864172892881 is 929609.

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

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., 610962652881 + 253210240000 = 781641^2 + 503200^2 .

It is not a de Polignac number, because 864172892881 - 2¹⁹ = 864172368593 is a prime.

It is a super-2 number, since 2×864172892881² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (864172892887) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 464805 + ... + 1394413.

Almost surely, 2^864172892881 is an apocalyptic number.

864172892881 is the 929609-th square number.

864172892881 is the 464805-th centered octagonal number.

It is an amenable number.

864172892881 is a deficient number, since it is larger than the sum of its proper divisors (929610).

864172892881 is an frugal number, since it uses more digits than its factorization.

864172892881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1859218 (or 929609 counting only the distinct ones).

The product of its digits is 24772608, while the sum is 64.

Multiplying 864172892881 by its sum of digits (64), we get a square (55307065144384 = 7436872²).

The spelling of 864172892881 in words is "eight hundred sixty-four billion, one hundred seventy-two million, eight hundred ninety-two thousand, eight hundred eighty-one".