85821813 has 48 divisors (see below), whose sum is σ = 157248000. Its totient is φ = 43806240.

The previous prime is 85821781. The next prime is 85821829. The reversal of 85821813 is 31812858.

It is not a de Polignac number, because 85821813 - 2⁵ = 85821781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85821863) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 39838 + ... + 41936.

It is an arithmetic number, because the mean of its divisors is an integer number (3276000).

Almost surely, 2^85821813 is an apocalyptic number.

It is an amenable number.

85821813 is a deficient number, since it is larger than the sum of its proper divisors (71426187).

85821813 is a wasteful number, since it uses less digits than its factorization.

85821813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2182 (or 2179 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 85821813 is about 9264.0063147647. The cubic root of 85821813 is about 441.0954334011.

The spelling of 85821813 in words is "eighty-five million, eight hundred twenty-one thousand, eight hundred thirteen".