81895973 has 2 divisors, whose sum is σ = 81895974. Its totient is φ = 81895972.

The previous prime is 81895969. The next prime is 81896051. The reversal of 81895973 is 37959818.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77827684 + 4068289 = 8822^2 + 2017^2 .

It is a cyclic number.

It is not a de Polignac number, because 81895973 - 2² = 81895969 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81895943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40947986 + 40947987.

It is an arithmetic number, because the mean of its divisors is an integer number (40947987).

Almost surely, 2^81895973 is an apocalyptic number.

It is an amenable number.

81895973 is a deficient number, since it is larger than the sum of its proper divisors (1).

81895973 is an equidigital number, since it uses as much as digits as its factorization.

81895973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 544320, while the sum is 50.

The square root of 81895973 is about 9049.6393850805. The cubic root of 81895973 is about 434.2643540137.

It can be divided in two parts, 8 and 1895973, that added together give a palindrome (1895981).

The spelling of 81895973 in words is "eighty-one million, eight hundred ninety-five thousand, nine hundred seventy-three".