85442809 has 2 divisors, whose sum is σ = 85442810. Its totient is φ = 85442808.

The previous prime is 85442783. The next prime is 85442831. The reversal of 85442809 is 90824458.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45158400 + 40284409 = 6720^2 + 6347^2 .

It is a cyclic number.

It is not a de Polignac number, because 85442809 - 2²⁵ = 51888377 is a prime.

It is not a weakly prime, because it can be changed into another prime (85442209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42721404 + 42721405.

It is an arithmetic number, because the mean of its divisors is an integer number (42721405).

Almost surely, 2^85442809 is an apocalyptic number.

It is an amenable number.

85442809 is a deficient number, since it is larger than the sum of its proper divisors (1).

85442809 is an equidigital number, since it uses as much as digits as its factorization.

85442809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 92160, while the sum is 40.

The square root of 85442809 is about 9243.5279520322. The cubic root of 85442809 is about 440.4451572555.

The spelling of 85442809 in words is "eighty-five million, four hundred forty-two thousand, eight hundred nine".