1961889911 has 2 divisors, whose sum is σ = 1961889912. Its totient is φ = 1961889910.

The previous prime is 1961889907. The next prime is 1961889931. The reversal of 1961889911 is 1199881691.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1961889911 - 2² = 1961889907 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1961889931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 980944955 + 980944956.

It is an arithmetic number, because the mean of its divisors is an integer number (980944956).

Almost surely, 2^1961889911 is an apocalyptic number.

1961889911 is a deficient number, since it is larger than the sum of its proper divisors (1).

1961889911 is an equidigital number, since it uses as much as digits as its factorization.

1961889911 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 53.

The square root of 1961889911 is about 44293.2264686148. The cubic root of 1961889911 is about 1251.8670575684.

It can be divided in two parts, 1961 and 889911, that multiplied together give a palindrome (1745115471).

The spelling of 1961889911 in words is "one billion, nine hundred sixty-one million, eight hundred eighty-nine thousand, nine hundred eleven".