81369863 has 4 divisors (see below), whose sum is σ = 81596880. Its totient is φ = 81142848.

The previous prime is 81369851. The next prime is 81369877. The reversal of 81369863 is 36896318.

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 81369863 - 2²⁰ = 80321287 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 (81309863) 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, 112970 + ... + 113687.

It is an arithmetic number, because the mean of its divisors is an integer number (20399220).

Almost surely, 2^81369863 is an apocalyptic number.

81369863 is a deficient number, since it is larger than the sum of its proper divisors (227017).

81369863 is a wasteful number, since it uses less digits than its factorization.

81369863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227016.

The product of its digits is 186624, while the sum is 44.

The square root of 81369863 is about 9020.5245412892. The cubic root of 81369863 is about 433.3324326740.

The spelling of 81369863 in words is "eighty-one million, three hundred sixty-nine thousand, eight hundred sixty-three".