81385836 has 24 divisors (see below), whose sum is σ = 217029120. Its totient is φ = 23253072.

The previous prime is 81385823. The next prime is 81385849. The reversal of 81385836 is 63858318.

It is an interprime number because it is at equal distance from previous prime (81385823) and next prime (81385849).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 484356 + ... + 484523.

It is an arithmetic number, because the mean of its divisors is an integer number (9042880).

Almost surely, 2^81385836 is an apocalyptic number.

It is an amenable number.

81385836 is an abundant number, since it is smaller than the sum of its proper divisors (135643284).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81385836 is a wasteful number, since it uses less digits than its factorization.

81385836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968893 (or 968891 counting only the distinct ones).

The product of its digits is 138240, while the sum is 42.

The square root of 81385836 is about 9021.4098676426. The cubic root of 81385836 is about 433.3607853746.

The spelling of 81385836 in words is "eighty-one million, three hundred eighty-five thousand, eight hundred thirty-six".