85581521 has 2 divisors, whose sum is σ = 85581522. Its totient is φ = 85581520.

The previous prime is 85581479. The next prime is 85581533. The reversal of 85581521 is 12518558.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55726225 + 29855296 = 7465^2 + 5464^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85581521 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (85581541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42790760 + 42790761.

It is an arithmetic number, because the mean of its divisors is an integer number (42790761).

Almost surely, 2^85581521 is an apocalyptic number.

It is an amenable number.

85581521 is a deficient number, since it is larger than the sum of its proper divisors (1).

85581521 is an equidigital number, since it uses as much as digits as its factorization.

85581521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16000, while the sum is 35.

The square root of 85581521 is about 9251.0281050270. The cubic root of 85581521 is about 440.6833750670.

The spelling of 85581521 in words is "eighty-five million, five hundred eighty-one thousand, five hundred twenty-one".