85251721 has 2 divisors, whose sum is σ = 85251722. Its totient is φ = 85251720.

The previous prime is 85251701. The next prime is 85251739. The reversal of 85251721 is 12715258.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57836025 + 27415696 = 7605^2 + 5236^2 .

It is a cyclic number.

It is not a de Polignac number, because 85251721 - 2¹⁵ = 85218953 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (85251701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42625860 + 42625861.

It is an arithmetic number, because the mean of its divisors is an integer number (42625861).

Almost surely, 2^85251721 is an apocalyptic number.

It is an amenable number.

85251721 is a deficient number, since it is larger than the sum of its proper divisors (1).

85251721 is an equidigital number, since it uses as much as digits as its factorization.

85251721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5600, while the sum is 31.

The square root of 85251721 is about 9233.1858532145. The cubic root of 85251721 is about 440.1165686328.

Adding to 85251721 its reverse (12715258), we get a palindrome (97966979).

The spelling of 85251721 in words is "eighty-five million, two hundred fifty-one thousand, seven hundred twenty-one".