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81869 is a prime number
BaseRepresentation
bin10011111111001101
311011022012
4103333031
510104434
61431005
7460454
oct237715
9134265
1081869
1156567
123b465
132b358
1421b9b
15193ce
hex13fcd

81869 has 2 divisors, whose sum is σ = 81870. Its totient is φ = 81868.

The previous prime is 81853. The next prime is 81883. The reversal of 81869 is 96818.

81869 is an esthetic number in base 11, because in such base its adjacent digits differ by 1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68644 + 13225 = 262^2 + 115^2 .

It is a cyclic number.

It is not a de Polignac number, because 81869 - 24 = 81853 is a prime.

It is a super-2 number, since 2×818692 = 13405066322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40934 + 40935.

It is an arithmetic number, because the mean of its divisors is an integer number (40935).

281869 is an apocalyptic number.

It is an amenable number.

81869 is a deficient number, since it is larger than the sum of its proper divisors (1).

81869 is an equidigital number, since it uses as much as digits as its factorization.

81869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 32.

The square root of 81869 is about 286.1275939157. The cubic root of 81869 is about 43.4216672798.

The spelling of 81869 in words is "eighty-one thousand, eight hundred sixty-nine".