83491021 has 2 divisors, whose sum is σ = 83491022. Its totient is φ = 83491020.

The previous prime is 83491013. The next prime is 83491027. The reversal of 83491021 is 12019438.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71588521 + 11902500 = 8461^2 + 3450^2 .

It is a cyclic number.

It is not a de Polignac number, because 83491021 - 2³ = 83491013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83491027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41745510 + 41745511.

It is an arithmetic number, because the mean of its divisors is an integer number (41745511).

Almost surely, 2^83491021 is an apocalyptic number.

It is an amenable number.

83491021 is a deficient number, since it is larger than the sum of its proper divisors (1).

83491021 is an equidigital number, since it uses as much as digits as its factorization.

83491021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 83491021 is about 9137.3421190191. The cubic root of 83491021 is about 437.0655645054.

The spelling of 83491021 in words is "eighty-three million, four hundred ninety-one thousand, twenty-one".