81556233 has 16 divisors (see below), whose sum is σ = 121153536. Its totient is φ = 48375440.

The previous prime is 81556217. The next prime is 81556243. The reversal of 81556233 is 33265518.

It is a cyclic number.

It is not a de Polignac number, because 81556233 - 2⁴ = 81556217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 81556194 and 81556203.

It is not an unprimeable number, because it can be changed into a prime (81556243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24741 + ... + 27842.

It is an arithmetic number, because the mean of its divisors is an integer number (7572096).

Almost surely, 2^81556233 is an apocalyptic number.

It is an amenable number.

81556233 is a deficient number, since it is larger than the sum of its proper divisors (39597303).

81556233 is a wasteful number, since it uses less digits than its factorization.

81556233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52644.

The product of its digits is 21600, while the sum is 33.

The square root of 81556233 is about 9030.8489634142. The cubic root of 81556233 is about 433.6630161070.

The spelling of 81556233 in words is "eighty-one million, five hundred fifty-six thousand, two hundred thirty-three".