81477191 has 8 divisors (see below), whose sum is σ = 82286400. Its totient is φ = 80671968.

The previous prime is 81477163. The next prime is 81477197. The reversal of 81477191 is 19177418.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81477191 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 (81477197) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54050 + ... + 55536.

It is an arithmetic number, because the mean of its divisors is an integer number (10285800).

Almost surely, 2^81477191 is an apocalyptic number.

81477191 is a deficient number, since it is larger than the sum of its proper divisors (809209).

81477191 is a wasteful number, since it uses less digits than its factorization.

81477191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1993.

The product of its digits is 14112, while the sum is 38.

The square root of 81477191 is about 9026.4716805627. The cubic root of 81477191 is about 433.5228728363.

The spelling of 81477191 in words is "eighty-one million, four hundred seventy-seven thousand, one hundred ninety-one".