118221581 has 2 divisors, whose sum is σ = 118221582. Its totient is φ = 118221580.

The previous prime is 118221539. The next prime is 118221601. The reversal of 118221581 is 185122811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76825225 + 41396356 = 8765^2 + 6434^2 .

It is an emirp because it is prime and its reverse (185122811) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-118221581 is a prime.

It is a super-2 number, since 2×118221581² = 27952684428279122, 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 (118221881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 59110790 + 59110791.

It is an arithmetic number, because the mean of its divisors is an integer number (59110791).

Almost surely, 2^118221581 is an apocalyptic number.

It is an amenable number.

118221581 is a deficient number, since it is larger than the sum of its proper divisors (1).

118221581 is an equidigital number, since it uses as much as digits as its factorization.

118221581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1280, while the sum is 29.

The square root of 118221581 is about 10872.9747999340. The cubic root of 118221581 is about 490.7936340598.

The spelling of 118221581 in words is "one hundred eighteen million, two hundred twenty-one thousand, five hundred eighty-one".