199906958561 has 2 divisors, whose sum is σ = 199906958562. Its totient is φ = 199906958560.

The previous prime is 199906958543. The next prime is 199906958623. The reversal of 199906958561 is 165859609991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190811712400 + 9095246161 = 436820^2 + 95369^2 .

It is a cyclic number.

It is not a de Polignac number, because 199906958561 - 2⁶ = 199906958497 is a prime.

It is a super-2 number, since 2×199906958561² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 199906958491 and 199906958500.

It is not a weakly prime, because it can be changed into another prime (199906958261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99953479280 + 99953479281.

It is an arithmetic number, because the mean of its divisors is an integer number (99953479281).

Almost surely, 2^199906958561 is an apocalyptic number.

It is an amenable number.

199906958561 is a deficient number, since it is larger than the sum of its proper divisors (1).

199906958561 is an equidigital number, since it uses as much as digits as its factorization.

199906958561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 47239200, while the sum is 68.

The spelling of 199906958561 in words is "one hundred ninety-nine billion, nine hundred six million, nine hundred fifty-eight thousand, five hundred sixty-one".