81552231 has 32 divisors (see below), whose sum is σ = 123594240. Its totient is φ = 53136000.

The previous prime is 81552223. The next prime is 81552241. The reversal of 81552231 is 13225518.

It is a happy number.

81552231 is a `hidden beast` number, since 81 + 552 + 2 + 31 = 666.

It is not a de Polignac number, because 81552231 - 2³ = 81552223 is a prime.

It is a super-2 number, since 2×81552231² = 13301532762154722, which contains 22 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 81552195 and 81552204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81552241) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 338271 + ... + 338511.

It is an arithmetic number, because the mean of its divisors is an integer number (3862320).

Almost surely, 2^81552231 is an apocalyptic number.

81552231 is a deficient number, since it is larger than the sum of its proper divisors (42042009).

81552231 is a wasteful number, since it uses less digits than its factorization.

81552231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484 (or 478 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 81552231 is about 9030.6273868431. The cubic root of 81552231 is about 433.6559226464.

Adding to 81552231 its reverse (13225518), we get a palindrome (94777749).

The spelling of 81552231 in words is "eighty-one million, five hundred fifty-two thousand, two hundred thirty-one".