83871721 has 2 divisors, whose sum is σ = 83871722. Its totient is φ = 83871720.

The previous prime is 83871707. The next prime is 83871737. The reversal of 83871721 is 12717838.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67831696 + 16040025 = 8236^2 + 4005^2 .

It is a cyclic number.

It is not a de Polignac number, because 83871721 - 2¹³ = 83863529 is a prime.

It is not a weakly prime, because it can be changed into another prime (83871791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41935860 + 41935861.

It is an arithmetic number, because the mean of its divisors is an integer number (41935861).

Almost surely, 2^83871721 is an apocalyptic number.

It is an amenable number.

83871721 is a deficient number, since it is larger than the sum of its proper divisors (1).

83871721 is an equidigital number, since it uses as much as digits as its factorization.

83871721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18816, while the sum is 37.

The square root of 83871721 is about 9158.1505228949. The cubic root of 83871721 is about 437.7288637668.

The spelling of 83871721 in words is "eighty-three million, eight hundred seventy-one thousand, seven hundred twenty-one".