118291981 has 2 divisors, whose sum is σ = 118291982. Its totient is φ = 118291980.

The previous prime is 118291963. The next prime is 118292021. The reversal of 118291981 is 189192811.

It is an a-pointer prime, because the next prime (118292021) can be obtained adding 118291981 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 105575625 + 12716356 = 10275^2 + 3566^2 .

It is a cyclic number.

It is not a de Polignac number, because 118291981 - 2⁵ = 118291949 is a prime.

It is a super-2 number, since 2×118291981² = 27985985537808722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (118291931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 59145990 + 59145991.

It is an arithmetic number, because the mean of its divisors is an integer number (59145991).

Almost surely, 2^118291981 is an apocalyptic number.

It is an amenable number.

118291981 is a deficient number, since it is larger than the sum of its proper divisors (1).

118291981 is an equidigital number, since it uses as much as digits as its factorization.

118291981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 40.

The square root of 118291981 is about 10876.2117026104. The cubic root of 118291981 is about 490.8910359480.

The spelling of 118291981 in words is "one hundred eighteen million, two hundred ninety-one thousand, nine hundred eighty-one".