81355474 has 4 divisors (see below), whose sum is σ = 122033214. Its totient is φ = 40677736.

The previous prime is 81355471. The next prime is 81355493. The reversal of 81355474 is 47455318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 47455318 = 2 ⋅23727659.

It can be written as a sum of positive squares in only one way, i.e., 46036225 + 35319249 = 6785^2 + 5943^2 .

It is not an unprimeable number, because it can be changed into a prime (81355471) 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 as a sum of consecutive naturals, namely, 20338867 + ... + 20338870.

Almost surely, 2^81355474 is an apocalyptic number.

81355474 is a deficient number, since it is larger than the sum of its proper divisors (40677740).

81355474 is a wasteful number, since it uses less digits than its factorization.

81355474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40677739.

The product of its digits is 67200, while the sum is 37.

The square root of 81355474 is about 9019.7269359998. The cubic root of 81355474 is about 433.3068884585.

The spelling of 81355474 in words is "eighty-one million, three hundred fifty-five thousand, four hundred seventy-four".