81045457 has 4 divisors (see below), whose sum is σ = 81088000. Its totient is φ = 81002916.

The previous prime is 81045413. The next prime is 81045473. The reversal of 81045457 is 75454018.

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: 75454018 = 2 ⋅37727009.

It is a cyclic number.

It is not a de Polignac number, because 81045457 - 2¹¹ = 81043409 is a prime.

It is a super-2 number, since 2×81045457² = 13136732200677698, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (81045487) 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, 18273 + ... + 22270.

It is an arithmetic number, because the mean of its divisors is an integer number (20272000).

Almost surely, 2^81045457 is an apocalyptic number.

It is an amenable number.

81045457 is a deficient number, since it is larger than the sum of its proper divisors (42543).

81045457 is a wasteful number, since it uses less digits than its factorization.

81045457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42542.

The product of its (nonzero) digits is 22400, while the sum is 34.

The square root of 81045457 is about 9002.5250346778. The cubic root of 81045457 is about 432.7557946459.

The spelling of 81045457 in words is "eighty-one million, forty-five thousand, four hundred fifty-seven".