81394633 has 2 divisors, whose sum is σ = 81394634. Its totient is φ = 81394632.

The previous prime is 81394627. The next prime is 81394661. The reversal of 81394633 is 33649318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50168889 + 31225744 = 7083^2 + 5588^2 .

It is a cyclic number.

It is not a de Polignac number, because 81394633 - 2⁵ = 81394601 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81394592 and 81394601.

It is not a weakly prime, because it can be changed into another prime (81334633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40697316 + 40697317.

It is an arithmetic number, because the mean of its divisors is an integer number (40697317).

Almost surely, 2^81394633 is an apocalyptic number.

It is an amenable number.

81394633 is a deficient number, since it is larger than the sum of its proper divisors (1).

81394633 is an equidigital number, since it uses as much as digits as its factorization.

81394633 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 37.

The square root of 81394633 is about 9021.8974168409. The cubic root of 81394633 is about 433.3763988100.

The spelling of 81394633 in words is "eighty-one million, three hundred ninety-four thousand, six hundred thirty-three".