199906954561 has 2 divisors, whose sum is σ = 199906954562. Its totient is φ = 199906954560.

The previous prime is 199906954459. The next prime is 199906954589. The reversal of 199906954561 is 165459609991.

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., 190375142400 + 9531812161 = 436320^2 + 97631^2 .

It is a cyclic number.

It is not a de Polignac number, because 199906954561 - 2⁷ = 199906954433 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 199906954493 and 199906954502.

It is not a weakly prime, because it can be changed into another prime (199906958561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99953477280 + 99953477281.

It is an arithmetic number, because the mean of its divisors is an integer number (99953477281).

Almost surely, 2^199906954561 is an apocalyptic number.

It is an amenable number.

199906954561 is a deficient number, since it is larger than the sum of its proper divisors (1).

199906954561 is an equidigital number, since it uses as much as digits as its factorization.

199906954561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23619600, while the sum is 64.

The spelling of 199906954561 in words is "one hundred ninety-nine billion, nine hundred six million, nine hundred fifty-four thousand, five hundred sixty-one".