81764 has 6 divisors (see below), whose sum is σ = 143094. Its totient is φ = 40880.
The previous prime is 81761. The next prime is 81769. The reversal of 81764 is 46718.
It can be written as a sum of positive squares in only one way, i.e., 78400 + 3364 = 280^2 + 58^2 .
It is not an unprimeable number, because it can be changed into a prime (81761) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10217 + ... + 10224.
It is an arithmetic number, because the mean of its divisors is an integer number (23849).
281764 is an apocalyptic number.
It is an amenable number.
81764 is a deficient number, since it is larger than the sum of its proper divisors (61330).
81764 is a wasteful number, since it uses less digits than its factorization.
81764 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 20445 (or 20443 counting only the distinct ones).
The product of its digits is 1344, while the sum is 26.
The square root of 81764 is about 285.9440504714. The cubic root of 81764 is about 43.4030960437.
The spelling of 81764 in words is "eighty-one thousand, seven hundred sixty-four".
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