81288282321 has 45 divisors (see below), whose sum is σ = 123294663723. Its totient is φ = 53372779200.

The previous prime is 81288282307. The next prime is 81288282389. The reversal of 81288282321 is 12328288218.

The square root of 81288282321 is 285111.

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., 80479448721 + 808833600 = 283689^2 + 28440^2 .

It is not a de Polignac number, because 81288282321 - 2²³ = 81279893713 is a prime.

It is a super-2 number, since 2×81288282321² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81288289321) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 202713721 + ... + 202714121.

Almost surely, 2^81288282321 is an apocalyptic number.

81288282321 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81288282321 is the 285111-st square number.

81288282321 is the 142556-th centered octagonal number.

It is an amenable number.

81288282321 is a deficient number, since it is larger than the sum of its proper divisors (42006381402).

81288282321 is an frugal number, since it uses more digits than its factorization.

81288282321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 972 (or 483 counting only the distinct ones).

The product of its digits is 196608, while the sum is 45.

It can be divided in two parts, 81288 and 282321, that added together give a square (363609 = 603²).

The spelling of 81288282321 in words is "eighty-one billion, two hundred eighty-eight million, two hundred eighty-two thousand, three hundred twenty-one".