199890637 has 2 divisors, whose sum is σ = 199890638. Its totient is φ = 199890636.

The previous prime is 199890623. The next prime is 199890689. The reversal of 199890637 is 736098991.

It is an a-pointer prime, because the next prime (199890689) can be obtained adding 199890637 to its sum of digits (52).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190274436 + 9616201 = 13794^2 + 3101^2 .

It is an emirp because it is prime and its reverse (736098991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199890637 - 2²⁷ = 65672909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199890037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99945318 + 99945319.

It is an arithmetic number, because the mean of its divisors is an integer number (99945319).

Almost surely, 2^199890637 is an apocalyptic number.

It is an amenable number.

199890637 is a deficient number, since it is larger than the sum of its proper divisors (1).

199890637 is an equidigital number, since it uses as much as digits as its factorization.

199890637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 734832, while the sum is 52.

The square root of 199890637 is about 14138.2685290668. The cubic root of 199890637 is about 584.6969350905.

The spelling of 199890637 in words is "one hundred ninety-nine million, eight hundred ninety thousand, six hundred thirty-seven".