85217621 has 2 divisors, whose sum is σ = 85217622. Its totient is φ = 85217620.

The previous prime is 85217611. The next prime is 85217647. The reversal of 85217621 is 12671258.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52852900 + 32364721 = 7270^2 + 5689^2 .

It is a cyclic number.

It is not a de Polignac number, because 85217621 - 2²² = 81023317 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 (85217611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42608810 + 42608811.

It is an arithmetic number, because the mean of its divisors is an integer number (42608811).

Almost surely, 2^85217621 is an apocalyptic number.

It is an amenable number.

85217621 is a deficient number, since it is larger than the sum of its proper divisors (1).

85217621 is an equidigital number, since it uses as much as digits as its factorization.

85217621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 32.

The square root of 85217621 is about 9231.3390686292. The cubic root of 85217621 is about 440.0578797826.

Adding to 85217621 its reverse (12671258), we get a palindrome (97888879).

The spelling of 85217621 in words is "eighty-five million, two hundred seventeen thousand, six hundred twenty-one".