83681821 has 2 divisors, whose sum is σ = 83681822. Its totient is φ = 83681820.

The previous prime is 83681789. The next prime is 83681831. The reversal of 83681821 is 12818638.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44368921 + 39312900 = 6661^2 + 6270^2 .

It is a cyclic number.

It is not a de Polignac number, because 83681821 - 2⁵ = 83681789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83681831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41840910 + 41840911.

It is an arithmetic number, because the mean of its divisors is an integer number (41840911).

Almost surely, 2^83681821 is an apocalyptic number.

It is an amenable number.

83681821 is a deficient number, since it is larger than the sum of its proper divisors (1).

83681821 is an equidigital number, since it uses as much as digits as its factorization.

83681821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18432, while the sum is 37.

The square root of 83681821 is about 9147.7768337449. The cubic root of 83681821 is about 437.3982496436.

The spelling of 83681821 in words is "eighty-three million, six hundred eighty-one thousand, eight hundred twenty-one".