81933847 has 2 divisors, whose sum is σ = 81933848. Its totient is φ = 81933846.

The previous prime is 81933821. The next prime is 81933853. The reversal of 81933847 is 74833918.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81933847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81933857) 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, 40966923 + 40966924.

It is an arithmetic number, because the mean of its divisors is an integer number (40966924).

Almost surely, 2^81933847 is an apocalyptic number.

81933847 is a deficient number, since it is larger than the sum of its proper divisors (1).

81933847 is an equidigital number, since it uses as much as digits as its factorization.

81933847 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 43.

The square root of 81933847 is about 9051.7317127719. The cubic root of 81933847 is about 434.3312876807.

The spelling of 81933847 in words is "eighty-one million, nine hundred thirty-three thousand, eight hundred forty-seven".