81833721 has 8 divisors (see below), whose sum is σ = 111433344. Its totient is φ = 53394960.

The previous prime is 81833711. The next prime is 81833723. The reversal of 81833721 is 12733818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81833721 - 2¹⁰ = 81832697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81833723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 290050 + ... + 290331.

It is an arithmetic number, because the mean of its divisors is an integer number (13929168).

Almost surely, 2^81833721 is an apocalyptic number.

It is an amenable number.

81833721 is a deficient number, since it is larger than the sum of its proper divisors (29599623).

81833721 is a wasteful number, since it uses less digits than its factorization.

81833721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580431.

The product of its digits is 8064, while the sum is 33.

The square root of 81833721 is about 9046.1992571466. The cubic root of 81833721 is about 434.1542929356.

The spelling of 81833721 in words is "eighty-one million, eight hundred thirty-three thousand, seven hundred twenty-one".