83971021 has 2 divisors, whose sum is σ = 83971022. Its totient is φ = 83971020.

The previous prime is 83971009. The next prime is 83971031. The reversal of 83971021 is 12017938.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75933796 + 8037225 = 8714^2 + 2835^2 .

It is a cyclic number.

It is not a de Polignac number, because 83971021 - 2⁷ = 83970893 is a prime.

It is a super-2 number, since 2×83971021² = 14102264735564882, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83971001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41985510 + 41985511.

It is an arithmetic number, because the mean of its divisors is an integer number (41985511).

Almost surely, 2^83971021 is an apocalyptic number.

It is an amenable number.

83971021 is a deficient number, since it is larger than the sum of its proper divisors (1).

83971021 is an equidigital number, since it uses as much as digits as its factorization.

83971021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 83971021 is about 9163.5703194770. The cubic root of 83971021 is about 437.9015454640.

Adding to 83971021 its reverse (12017938), we get a palindrome (95988959).

The spelling of 83971021 in words is "eighty-three million, nine hundred seventy-one thousand, twenty-one".