85621009 has 2 divisors, whose sum is σ = 85621010. Its totient is φ = 85621008.

The previous prime is 85621001. The next prime is 85621013. The reversal of 85621009 is 90012658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76947984 + 8673025 = 8772^2 + 2945^2 .

It is a cyclic number.

It is not a de Polignac number, because 85621009 - 2³ = 85621001 is a prime.

It is not a weakly prime, because it can be changed into another prime (85621001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42810504 + 42810505.

It is an arithmetic number, because the mean of its divisors is an integer number (42810505).

Almost surely, 2^85621009 is an apocalyptic number.

It is an amenable number.

85621009 is a deficient number, since it is larger than the sum of its proper divisors (1).

85621009 is an equidigital number, since it uses as much as digits as its factorization.

85621009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 85621009 is about 9253.1621081661. The cubic root of 85621009 is about 440.7511429261.

The spelling of 85621009 in words is "eighty-five million, six hundred twenty-one thousand, nine".