81328211 has 4 divisors (see below), whose sum is σ = 81360624. Its totient is φ = 81295800.

The previous prime is 81328201. The next prime is 81328213. The reversal of 81328211 is 11282318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11282318 = 2 ⋅5641159.

It is a cyclic number.

It is not a de Polignac number, because 81328211 - 2¹⁰ = 81327187 is a prime.

It is a super-2 number, since 2×81328211² = 13228555808921042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81328213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12095 + ... + 17576.

It is an arithmetic number, because the mean of its divisors is an integer number (20340156).

Almost surely, 2^81328211 is an apocalyptic number.

81328211 is a deficient number, since it is larger than the sum of its proper divisors (32413).

81328211 is a wasteful number, since it uses less digits than its factorization.

81328211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32412.

The product of its digits is 768, while the sum is 26.

The square root of 81328211 is about 9018.2155108425. The cubic root of 81328211 is about 433.2584812855.

The spelling of 81328211 in words is "eighty-one million, three hundred twenty-eight thousand, two hundred eleven".