185500981 has 2 divisors, whose sum is σ = 185500982. Its totient is φ = 185500980.

The previous prime is 185500979. The next prime is 185501033. The reversal of 185500981 is 189005581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 141491025 + 44009956 = 11895^2 + 6634^2 .

It is a cyclic number.

It is not a de Polignac number, because 185500981 - 2¹ = 185500979 is a prime.

It is a super-2 number, since 2×185500981² = 68821227903924722, which contains 22 as substring.

Together with 185500979, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 185500981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (185500951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 92750490 + 92750491.

It is an arithmetic number, because the mean of its divisors is an integer number (92750491).

Almost surely, 2^185500981 is an apocalyptic number.

It is an amenable number.

185500981 is a deficient number, since it is larger than the sum of its proper divisors (1).

185500981 is an equidigital number, since it uses as much as digits as its factorization.

185500981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 37.

The square root of 185500981 is about 13619.8744854716. The cubic root of 185500981 is about 570.3158001751.

The spelling of 185500981 in words is "one hundred eighty-five million, five hundred thousand, nine hundred eighty-one".