85639819 has 4 divisors (see below), whose sum is σ = 86487840. Its totient is φ = 84791800.

The previous prime is 85639811. The next prime is 85639837. The reversal of 85639819 is 91893658.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 85639819 - 2³ = 85639811 is a prime.

It is a super-2 number, since 2×85639819² = 14668357196705522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (85639811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 423859 + ... + 424060.

It is an arithmetic number, because the mean of its divisors is an integer number (21621960).

Almost surely, 2^85639819 is an apocalyptic number.

85639819 is a deficient number, since it is larger than the sum of its proper divisors (848021).

85639819 is a wasteful number, since it uses less digits than its factorization.

85639819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 848020.

The product of its digits is 466560, while the sum is 49.

The square root of 85639819 is about 9254.1784616464. The cubic root of 85639819 is about 440.7834166327.

The spelling of 85639819 in words is "eighty-five million, six hundred thirty-nine thousand, eight hundred nineteen".