81678971 has 4 divisors (see below), whose sum is σ = 89104344. Its totient is φ = 74253600.

The previous prime is 81678941. The next prime is 81678977. The reversal of 81678971 is 17987618.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81678971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81678977) 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, 3712670 + ... + 3712691.

It is an arithmetic number, because the mean of its divisors is an integer number (22276086).

Almost surely, 2^81678971 is an apocalyptic number.

81678971 is a deficient number, since it is larger than the sum of its proper divisors (7425373).

81678971 is a wasteful number, since it uses less digits than its factorization.

81678971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7425372.

The product of its digits is 169344, while the sum is 47.

The square root of 81678971 is about 9037.6418937685. The cubic root of 81678971 is about 433.8804540241.

The spelling of 81678971 in words is "eighty-one million, six hundred seventy-eight thousand, nine hundred seventy-one".