81077533 has 4 divisors (see below), whose sum is σ = 83873340. Its totient is φ = 78281728.

The previous prime is 81077531. The next prime is 81077537. The reversal of 81077533 is 33577018.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 37491129 + 43586404 = 6123^2 + 6602^2 .

It is a cyclic number.

It is not a de Polignac number, because 81077533 - 2¹ = 81077531 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 (81077531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1397860 + ... + 1397917.

It is an arithmetic number, because the mean of its divisors is an integer number (20968335).

Almost surely, 2^81077533 is an apocalyptic number.

It is an amenable number.

81077533 is a deficient number, since it is larger than the sum of its proper divisors (2795807).

81077533 is a wasteful number, since it uses less digits than its factorization.

81077533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2795806.

The product of its (nonzero) digits is 17640, while the sum is 34.

The square root of 81077533 is about 9004.3063586264. The cubic root of 81077533 is about 432.8128788408.

The spelling of 81077533 in words is "eighty-one million, seventy-seven thousand, five hundred thirty-three".