20161991743 has 2 divisors, whose sum is σ = 20161991744. Its totient is φ = 20161991742.

The previous prime is 20161991741. The next prime is 20161991749. The reversal of 20161991743 is 34719916102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20161991743 - 2¹ = 20161991741 is a prime.

It is a super-2 number, since 2×20161991743² (a number of 21 digits) contains 22 as substring.

Together with 20161991741, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20161991743.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20161991741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10080995871 + 10080995872.

It is an arithmetic number, because the mean of its divisors is an integer number (10080995872).

Almost surely, 2^20161991743 is an apocalyptic number.

20161991743 is a deficient number, since it is larger than the sum of its proper divisors (1).

20161991743 is an equidigital number, since it uses as much as digits as its factorization.

20161991743 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 43.

The spelling of 20161991743 in words is "twenty billion, one hundred sixty-one million, nine hundred ninety-one thousand, seven hundred forty-three".