81839633 has 2 divisors, whose sum is σ = 81839634. Its totient is φ = 81839632.

The previous prime is 81839627. The next prime is 81839651. The reversal of 81839633 is 33693818.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81414529 + 425104 = 9023^2 + 652^2 .

It is a cyclic number.

It is not a de Polignac number, because 81839633 - 2⁴ = 81839617 is a prime.

It is not a weakly prime, because it can be changed into another prime (81839623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40919816 + 40919817.

It is an arithmetic number, because the mean of its divisors is an integer number (40919817).

Almost surely, 2^81839633 is an apocalyptic number.

It is an amenable number.

81839633 is a deficient number, since it is larger than the sum of its proper divisors (1).

81839633 is an equidigital number, since it uses as much as digits as its factorization.

81839633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 41.

The square root of 81839633 is about 9046.5260183122. The cubic root of 81839633 is about 434.1647477063.

The spelling of 81839633 in words is "eighty-one million, eight hundred thirty-nine thousand, six hundred thirty-three".