81774481 has 4 divisors (see below), whose sum is σ = 82568512. Its totient is φ = 80980452.

The previous prime is 81774479. The next prime is 81774487. The reversal of 81774481 is 18447718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18447718 = 2 ⋅9223859.

It is a cyclic number.

It is not a de Polignac number, because 81774481 - 2¹ = 81774479 is a prime.

It is a super-2 number, since 2×81774481² = 13374131485638722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81774487) 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, 396861 + ... + 397066.

It is an arithmetic number, because the mean of its divisors is an integer number (20642128).

Almost surely, 2^81774481 is an apocalyptic number.

It is an amenable number.

81774481 is a deficient number, since it is larger than the sum of its proper divisors (794031).

81774481 is a wasteful number, since it uses less digits than its factorization.

81774481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 794030.

The product of its digits is 50176, while the sum is 40.

The square root of 81774481 is about 9042.9243610682. The cubic root of 81774481 is about 434.0495052082.

The spelling of 81774481 in words is "eighty-one million, seven hundred seventy-four thousand, four hundred eighty-one".