85831021 has 2 divisors, whose sum is σ = 85831022. Its totient is φ = 85831020.

The previous prime is 85830989. The next prime is 85831027. The reversal of 85831021 is 12013858.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67469796 + 18361225 = 8214^2 + 4285^2 .

It is a cyclic number.

It is not a de Polignac number, because 85831021 - 2⁵ = 85830989 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 (85831027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42915510 + 42915511.

It is an arithmetic number, because the mean of its divisors is an integer number (42915511).

Almost surely, 2^85831021 is an apocalyptic number.

It is an amenable number.

85831021 is a deficient number, since it is larger than the sum of its proper divisors (1).

85831021 is an equidigital number, since it uses as much as digits as its factorization.

85831021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 85831021 is about 9264.5032786437. The cubic root of 85831021 is about 441.1112081844. Note that the first 3 decimals are identical.

Adding to 85831021 its reverse (12013858), we get a palindrome (97844879).

It can be divided in two parts, 8583 and 1021, that added together give a square (9604 = 98²).

The spelling of 85831021 in words is "eighty-five million, eight hundred thirty-one thousand, twenty-one".