81916777 has 8 divisors (see below), whose sum is σ = 85573440. Its totient is φ = 78268080.

The previous prime is 81916699. The next prime is 81916781. The reversal of 81916777 is 77761918.

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

It is not a de Polignac number, because 81916777 - 2⁷ = 81916649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81926777) 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, 30474 + ... + 33052.

It is an arithmetic number, because the mean of its divisors is an integer number (10696680).

Almost surely, 2^81916777 is an apocalyptic number.

It is an amenable number.

81916777 is a deficient number, since it is larger than the sum of its proper divisors (3656663).

81916777 is a wasteful number, since it uses less digits than its factorization.

81916777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3983.

The product of its digits is 148176, while the sum is 46.

The square root of 81916777 is about 9050.7887501587. The cubic root of 81916777 is about 434.3011228982.

The spelling of 81916777 in words is "eighty-one million, nine hundred sixteen thousand, seven hundred seventy-seven".