83218021 has 2 divisors, whose sum is σ = 83218022. Its totient is φ = 83218020.

The previous prime is 83218001. The next prime is 83218061. The reversal of 83218021 is 12081238.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76912900 + 6305121 = 8770^2 + 2511^2 .

It is a cyclic number.

It is not a de Polignac number, because 83218021 - 2⁵ = 83217989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83218001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41609010 + 41609011.

It is an arithmetic number, because the mean of its divisors is an integer number (41609011).

Almost surely, 2^83218021 is an apocalyptic number.

It is an amenable number.

83218021 is a deficient number, since it is larger than the sum of its proper divisors (1).

83218021 is an equidigital number, since it uses as much as digits as its factorization.

83218021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 83218021 is about 9122.3911887180. The cubic root of 83218021 is about 436.5886701656.

Adding to 83218021 its reverse (12081238), we get a palindrome (95299259).

The spelling of 83218021 in words is "eighty-three million, two hundred eighteen thousand, twenty-one".