83205781 has 2 divisors, whose sum is σ = 83205782. Its totient is φ = 83205780.

The previous prime is 83205763. The next prime is 83205797. The reversal of 83205781 is 18750238.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46117681 + 37088100 = 6791^2 + 6090^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-83205781 is a prime.

It is a super-2 number, since 2×83205781² = 13846403983639922, which contains 22 as substring.

It is equal to p_4845490 and since 83205781 and 4845490 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83205751) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41602890 + 41602891.

It is an arithmetic number, because the mean of its divisors is an integer number (41602891).

Almost surely, 2^83205781 is an apocalyptic number.

It is an amenable number.

83205781 is a deficient number, since it is larger than the sum of its proper divisors (1).

83205781 is an equidigital number, since it uses as much as digits as its factorization.

83205781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 83205781 is about 9121.7202873142. The cubic root of 83205781 is about 436.5672641157.

The spelling of 83205781 in words is "eighty-three million, two hundred five thousand, seven hundred eighty-one".