81457477 has 4 divisors (see below), whose sum is σ = 81478656. Its totient is φ = 81436300.

The previous prime is 81457469. The next prime is 81457543. The reversal of 81457477 is 77475418.

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 81457477 - 2³ = 81457469 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 (81457177) 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, 3013 + ... + 13114.

It is an arithmetic number, because the mean of its divisors is an integer number (20369664).

Almost surely, 2^81457477 is an apocalyptic number.

It is an amenable number.

81457477 is a deficient number, since it is larger than the sum of its proper divisors (21179).

81457477 is a wasteful number, since it uses less digits than its factorization.

81457477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21178.

The product of its digits is 219520, while the sum is 43.

The square root of 81457477 is about 9025.3796042050. The cubic root of 81457477 is about 433.4879053434.

The spelling of 81457477 in words is "eighty-one million, four hundred fifty-seven thousand, four hundred seventy-seven".