83870021 has 2 divisors, whose sum is σ = 83870022. Its totient is φ = 83870020.

The previous prime is 83869987. The next prime is 83870041. The reversal of 83870021 is 12007838.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63520900 + 20349121 = 7970^2 + 4511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-83870021 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83870041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41935010 + 41935011.

It is an arithmetic number, because the mean of its divisors is an integer number (41935011).

Almost surely, 2^83870021 is an apocalyptic number.

It is an amenable number.

83870021 is a deficient number, since it is larger than the sum of its proper divisors (1).

83870021 is an equidigital number, since it uses as much as digits as its factorization.

83870021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 83870021 is about 9158.0577089250. The cubic root of 83870021 is about 437.7259062976.

Adding to 83870021 its reverse (12007838), we get a palindrome (95877859).

The spelling of 83870021 in words is "eighty-three million, eight hundred seventy thousand, twenty-one".