81635823 has 8 divisors (see below), whose sum is σ = 120942000. Its totient is φ = 54423864.

The previous prime is 81635821. The next prime is 81635831. The reversal of 81635823 is 32853618.

It is not a de Polignac number, because 81635823 - 2¹ = 81635821 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81635821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1511748 + ... + 1511801.

It is an arithmetic number, because the mean of its divisors is an integer number (15117750).

Almost surely, 2^81635823 is an apocalyptic number.

81635823 is a deficient number, since it is larger than the sum of its proper divisors (39306177).

81635823 is a wasteful number, since it uses less digits than its factorization.

81635823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3023558 (or 3023552 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 81635823 is about 9035.2544513146. The cubic root of 81635823 is about 433.8040395316.

The spelling of 81635823 in words is "eighty-one million, six hundred thirty-five thousand, eight hundred twenty-three".