81977 has 8 divisors (see below), whose sum is σ = 96000. Its totient is φ = 69972.
The previous prime is 81973. The next prime is 82003. The reversal of 81977 is 77918.
Added to its reverse (77918) it gives a triangular number (159895 = T565).
It is not a de Polignac number, because 81977 - 22 = 81973 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (81971) 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, 224 + ... + 462.
It is an arithmetic number, because the mean of its divisors is an integer number (12000).
281977 is an apocalyptic number.
It is an amenable number.
81977 is a deficient number, since it is larger than the sum of its proper divisors (14023).
81977 is an equidigital number, since it uses as much as digits as its factorization.
81977 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 260 (or 246 counting only the distinct ones).
The product of its digits is 3528, while the sum is 32.
The square root of 81977 is about 286.3162587070. The cubic root of 81977 is about 43.4407525643.
Adding to 81977 its reverse (77918), we get a triangular number (159895 = T565).
The spelling of 81977 in words is "eighty-one thousand, nine hundred seventy-seven".
• e-mail: info -at- numbersaplenty.com • Privacy notice • done in 0.061 sec. • engine limits •