81536783 has 4 divisors (see below), whose sum is σ = 82132080. Its totient is φ = 80941488.

The previous prime is 81536773. The next prime is 81536797. The reversal of 81536783 is 38763518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 38763518 = 2 ⋅19381759.

It is a cyclic number.

It is not a de Polignac number, because 81536783 - 2¹⁴ = 81520399 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81536783.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81536713) 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, 297443 + ... + 297716.

It is an arithmetic number, because the mean of its divisors is an integer number (20533020).

Almost surely, 2^81536783 is an apocalyptic number.

81536783 is a deficient number, since it is larger than the sum of its proper divisors (595297).

81536783 is a wasteful number, since it uses less digits than its factorization.

81536783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 595296.

The product of its digits is 120960, while the sum is 41.

The square root of 81536783 is about 9029.7720347747. The cubic root of 81536783 is about 433.6285392152.

The spelling of 81536783 in words is "eighty-one million, five hundred thirty-six thousand, seven hundred eighty-three".