81352231 has 4 divisors (see below), whose sum is σ = 81453600. Its totient is φ = 81250864.

The previous prime is 81352217. The next prime is 81352247. The reversal of 81352231 is 13225318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13225318 = 2 ⋅6612659.

It is a cyclic number.

It is not a de Polignac number, because 81352231 - 2⁵ = 81352199 is a prime.

It is a super-2 number, since 2×81352231² = 13236370977354722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81352196 and 81352205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81352261) 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, 49471 + ... + 51088.

It is an arithmetic number, because the mean of its divisors is an integer number (20363400).

Almost surely, 2^81352231 is an apocalyptic number.

81352231 is a deficient number, since it is larger than the sum of its proper divisors (101369).

81352231 is a wasteful number, since it uses less digits than its factorization.

81352231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101368.

The product of its digits is 1440, while the sum is 25.

The square root of 81352231 is about 9019.5471615819. The cubic root of 81352231 is about 433.3011308746.

Adding to 81352231 its reverse (13225318), we get a palindrome (94577549).

The spelling of 81352231 in words is "eighty-one million, three hundred fifty-two thousand, two hundred thirty-one".