81933517 has 2 divisors, whose sum is σ = 81933518. Its totient is φ = 81933516.

The previous prime is 81933499. The next prime is 81933541. The reversal of 81933517 is 71533918.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56340036 + 25593481 = 7506^2 + 5059^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81933517 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81933547) 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 as a sum of consecutive naturals, namely, 40966758 + 40966759.

It is an arithmetic number, because the mean of its divisors is an integer number (40966759).

Almost surely, 2^81933517 is an apocalyptic number.

It is an amenable number.

81933517 is a deficient number, since it is larger than the sum of its proper divisors (1).

81933517 is an equidigital number, since it uses as much as digits as its factorization.

81933517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 37.

The square root of 81933517 is about 9051.7134841973. The cubic root of 81933517 is about 434.3307045700.

The spelling of 81933517 in words is "eighty-one million, nine hundred thirty-three thousand, five hundred seventeen".