100981 has 2 divisors, whose sum is σ = 100982. Its totient is φ = 100980.

The previous prime is 100957. The next prime is 100987. The reversal of 100981 is 189001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54756 + 46225 = 234^2 + 215^2 .

It is a cyclic number.

It is not a de Polignac number, because 100981 - 2⁷ = 100853 is a prime.

It is a super-2 number, since 2×100981² = 20394324722, which contains 22 as substring.

100981 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50490 + 50491.

It is an arithmetic number, because the mean of its divisors is an integer number (50491).

2¹⁰⁰⁹⁸¹ is an apocalyptic number.

It is an amenable number.

100981 is a deficient number, since it is larger than the sum of its proper divisors (1).

100981 is an equidigital number, since it uses as much as digits as its factorization.

100981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 100981 is about 317.7750776886. The cubic root of 100981 is about 46.5671746579.

Adding to 100981 its reverse (189001), we get a palindrome (289982).

It can be divided in two parts, 100 and 981, that added together give a triangular number (1081 = T₄₆).

The spelling of 100981 in words is "one hundred thousand, nine hundred eighty-one".