85490021 has 2 divisors, whose sum is σ = 85490022. Its totient is φ = 85490020.

The previous prime is 85489981. The next prime is 85490023. The reversal of 85490021 is 12009458.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80820100 + 4669921 = 8990^2 + 2161^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85490021 is a prime.

Together with 85490023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85490023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42745010 + 42745011.

It is an arithmetic number, because the mean of its divisors is an integer number (42745011).

Almost surely, 2^85490021 is an apocalyptic number.

It is an amenable number.

85490021 is a deficient number, since it is larger than the sum of its proper divisors (1).

85490021 is an equidigital number, since it uses as much as digits as its factorization.

85490021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 85490021 is about 9246.0813861873. The cubic root of 85490021 is about 440.5262659651.

Adding to 85490021 its reverse (12009458), we get a palindrome (97499479).

The spelling of 85490021 in words is "eighty-five million, four hundred ninety thousand, twenty-one".