81493775 has 24 divisors (see below), whose sum is σ = 111909504. Its totient is φ = 58370400.

The previous prime is 81493751. The next prime is 81493777. The reversal of 81493775 is 57739418.

It is not a de Polignac number, because 81493775 - 2¹⁰ = 81492751 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 (81493777) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16214 + ... + 20636.

It is an arithmetic number, because the mean of its divisors is an integer number (4662896).

Almost surely, 2^81493775 is an apocalyptic number.

81493775 is a deficient number, since it is larger than the sum of its proper divisors (30415729).

81493775 is a wasteful number, since it uses less digits than its factorization.

81493775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4511 (or 4506 counting only the distinct ones).

The product of its digits is 211680, while the sum is 44.

The square root of 81493775 is about 9027.3902651874. The cubic root of 81493775 is about 433.5522841579.

The spelling of 81493775 in words is "eighty-one million, four hundred ninety-three thousand, seven hundred seventy-five".