81061583 has 4 divisors (see below), whose sum is σ = 83856840. Its totient is φ = 78266328.

The previous prime is 81061553. The next prime is 81061681. The reversal of 81061583 is 38516018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 38516018 = 2 ⋅19258009.

It is a cyclic number.

It is not a de Polignac number, because 81061583 - 2¹⁴ = 81045199 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 (81061523) 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, 1397585 + ... + 1397642.

It is an arithmetic number, because the mean of its divisors is an integer number (20964210).

Almost surely, 2^81061583 is an apocalyptic number.

81061583 is a deficient number, since it is larger than the sum of its proper divisors (2795257).

81061583 is a wasteful number, since it uses less digits than its factorization.

81061583 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2795256.

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 81061583 is about 9003.4206277392. The cubic root of 81061583 is about 432.7844952352.

The spelling of 81061583 in words is "eighty-one million, sixty-one thousand, five hundred eighty-three".