81322272 has 96 divisors (see below), whose sum is σ = 241234560. Its totient is φ = 26645760.

The previous prime is 81322259. The next prime is 81322277. The reversal of 81322272 is 27222318.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×81322272² = 13226623846483968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81322277) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 51933 + ... + 53475.

It is an arithmetic number, because the mean of its divisors is an integer number (2512860).

Almost surely, 2^81322272 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81322272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120617280).

81322272 is an abundant number, since it is smaller than the sum of its proper divisors (159912288).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81322272 is a wasteful number, since it uses less digits than its factorization.

81322272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1623 (or 1609 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 81322272 is about 9017.8862268272. The cubic root of 81322272 is about 433.2479347821.

It can be divided in two parts, 8132 and 2272, that added together give a square (10404 = 102²).

The spelling of 81322272 in words is "eighty-one million, three hundred twenty-two thousand, two hundred seventy-two".