200020021991 has 2 divisors, whose sum is σ = 200020021992. Its totient is φ = 200020021990.

The previous prime is 200020021979. The next prime is 200020022009. The reversal of 200020021991 is 199120020002.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-200020021991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 200020021991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (200020021921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100010010995 + 100010010996.

It is an arithmetic number, because the mean of its divisors is an integer number (100010010996).

Almost surely, 2^200020021991 is an apocalyptic number.

200020021991 is a deficient number, since it is larger than the sum of its proper divisors (1).

200020021991 is an equidigital number, since it uses as much as digits as its factorization.

200020021991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

Adding to 200020021991 its reverse (199120020002), we get a palindrome (399140041993).

The spelling of 200020021991 in words is "two hundred billion, twenty million, twenty-one thousand, nine hundred ninety-one".