81328264 has 8 divisors (see below), whose sum is σ = 152490510. Its totient is φ = 40664128.

The previous prime is 81328249. The next prime is 81328307. The reversal of 81328264 is 46282318.

It can be written as a sum of positive squares in only one way, i.e., 79959364 + 1368900 = 8942^2 + 1170^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×81328264² = 13228573050507392, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5083009 + ... + 5083024.

Almost surely, 2^81328264 is an apocalyptic number.

It is an amenable number.

81328264 is a deficient number, since it is larger than the sum of its proper divisors (71162246).

81328264 is a wasteful number, since it uses less digits than its factorization.

81328264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10166039 (or 10166035 counting only the distinct ones).

The product of its digits is 18432, while the sum is 34.

The square root of 81328264 is about 9018.2184493391. The cubic root of 81328264 is about 433.2585754008.

The spelling of 81328264 in words is "eighty-one million, three hundred twenty-eight thousand, two hundred sixty-four".