85623821 has 4 divisors (see below), whose sum is σ = 85650492. Its totient is φ = 85597152.

The previous prime is 85623721. The next prime is 85623841. The reversal of 85623821 is 12832658.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12832658 = 2 ⋅6416329.

It can be written as a sum of positive squares in 2 ways, for example, as 33582025 + 52041796 = 5795^2 + 7214^2 .

It is a cyclic number.

It is not a de Polignac number, because 85623821 - 2¹⁸ = 85361677 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85623841) 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, 7736 + ... + 15201.

It is an arithmetic number, because the mean of its divisors is an integer number (21412623).

Almost surely, 2^85623821 is an apocalyptic number.

It is an amenable number.

85623821 is a deficient number, since it is larger than the sum of its proper divisors (26671).

85623821 is a wasteful number, since it uses less digits than its factorization.

85623821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26670.

The product of its digits is 23040, while the sum is 35.

The square root of 85623821 is about 9253.3140549751. The cubic root of 85623821 is about 440.7559679827.

The spelling of 85623821 in words is "eighty-five million, six hundred twenty-three thousand, eight hundred twenty-one".