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65981 is a prime number
BaseRepresentation
bin10000000110111101
310100111202
4100012331
54102411
61225245
7363236
oct200675
9110452
1065981
1145633
1232225
1324056
141a08d
151483b
hex101bd

65981 has 2 divisors, whose sum is σ = 65982. Its totient is φ = 65980.

The previous prime is 65963. The next prime is 65983. The reversal of 65981 is 18956.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62500 + 3481 = 250^2 + 59^2 .

It is a cyclic number.

It is not a de Polignac number, because 65981 - 214 = 49597 is a prime.

It is a super-3 number, since 3×659813 = 861743338413423, which contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 65983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 65981.

It is not a weakly prime, because it can be changed into another prime (65983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32990 + 32991.

It is an arithmetic number, because the mean of its divisors is an integer number (32991).

265981 is an apocalyptic number.

It is an amenable number.

65981 is a deficient number, since it is larger than the sum of its proper divisors (1).

65981 is an equidigital number, since it uses as much as digits as its factorization.

65981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 29.

The square root of 65981 is about 256.8676702117. The cubic root of 65981 is about 40.4085218764.

The spelling of 65981 in words is "sixty-five thousand, nine hundred eighty-one".