81395774 has 4 divisors (see below), whose sum is σ = 122093664. Its totient is φ = 40697886.

The previous prime is 81395771. The next prime is 81395807. The reversal of 81395774 is 47759318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 47759318 = 2 ⋅23879659.

It is a super-3 number, since 3×81395774³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81395771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20348942 + ... + 20348945.

It is an arithmetic number, because the mean of its divisors is an integer number (30523416).

Almost surely, 2^81395774 is an apocalyptic number.

81395774 is a deficient number, since it is larger than the sum of its proper divisors (40697890).

81395774 is a wasteful number, since it uses less digits than its factorization.

81395774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40697889.

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

The square root of 81395774 is about 9021.9606516544. The cubic root of 81395774 is about 433.3784238418.

The spelling of 81395774 in words is "eighty-one million, three hundred ninety-five thousand, seven hundred seventy-four".