199973581 has 2 divisors, whose sum is σ = 199973582. Its totient is φ = 199973580.

The previous prime is 199973549. The next prime is 199973593. The reversal of 199973581 is 185379991.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 127893481 + 72080100 = 11309^2 + 8490^2 .

It is a cyclic number.

It is not a de Polignac number, because 199973581 - 2⁵ = 199973549 is a prime.

It is a super-2 number, since 2×199973581² = 79978866195927122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199973681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99986790 + 99986791.

It is an arithmetic number, because the mean of its divisors is an integer number (99986791).

Almost surely, 2^199973581 is an apocalyptic number.

It is an amenable number.

199973581 is a deficient number, since it is larger than the sum of its proper divisors (1).

199973581 is an equidigital number, since it uses as much as digits as its factorization.

199973581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 612360, while the sum is 52.

The square root of 199973581 is about 14141.2015401804. The cubic root of 199973581 is about 584.7777966338. Note that the first 4 decimals are identical.

The spelling of 199973581 in words is "one hundred ninety-nine million, nine hundred seventy-three thousand, five hundred eighty-one".