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133981 is a prime number
BaseRepresentation
bin100000101101011101
320210210021
4200231131
513241411
62512141
71065421
oct405535
9223707
10133981
1191731
1265651
1348ca3
1436b81
1529a71
hex20b5d

133981 has 2 divisors, whose sum is σ = 133982. Its totient is φ = 133980.

The previous prime is 133979. The next prime is 133993. The reversal of 133981 is 189331.

133981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133956 + 25 = 366^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 133981 - 21 = 133979 is a prime.

It is a super-2 number, since 2×1339812 = 35901816722, which contains 22 as substring.

Together with 133979, it forms a pair of twin primes.

133981 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66990 + 66991.

It is an arithmetic number, because the mean of its divisors is an integer number (66991).

2133981 is an apocalyptic number.

133981 is the 232-nd centered pentagonal number.

It is an amenable number.

133981 is a deficient number, since it is larger than the sum of its proper divisors (1).

133981 is an equidigital number, since it uses as much as digits as its factorization.

133981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 25.

The square root of 133981 is about 366.0341514121. The cubic root of 133981 is about 51.1698807635.

Subtracting from 133981 its sum of digits (25), we obtain a square (133956 = 3662).

The spelling of 133981 in words is "one hundred thirty-three thousand, nine hundred eighty-one".