81457973 has 4 divisors (see below), whose sum is σ = 84999648. Its totient is φ = 77916300.

The previous prime is 81457969. The next prime is 81458009. The reversal of 81457973 is 37975418.

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.

It is a cyclic number.

It is not a de Polignac number, because 81457973 - 2² = 81457969 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 (81457913) 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, 1770803 + ... + 1770848.

It is an arithmetic number, because the mean of its divisors is an integer number (21249912).

Almost surely, 2^81457973 is an apocalyptic number.

It is an amenable number.

81457973 is a deficient number, since it is larger than the sum of its proper divisors (3541675).

81457973 is a wasteful number, since it uses less digits than its factorization.

81457973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3541674.

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

The square root of 81457973 is about 9025.4070822318. The cubic root of 81457973 is about 433.4887851872.

The spelling of 81457973 in words is "eighty-one million, four hundred fifty-seven thousand, nine hundred seventy-three".