20105953251949 has 2 divisors, whose sum is σ = 20105953251950. Its totient is φ = 20105953251948.

The previous prime is 20105953251947. The next prime is 20105953252003. The reversal of 20105953251949 is 94915235950102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15272190441225 + 4833762810724 = 3907965^2 + 2198582^2 .

It is a cyclic number.

It is not a de Polignac number, because 20105953251949 - 2¹ = 20105953251947 is a prime.

Together with 20105953251947, 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 20105953251949.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20105953251947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10052976625974 + 10052976625975.

It is an arithmetic number, because the mean of its divisors is an integer number (10052976625975).

Almost surely, 2^{20105953251949} is an apocalyptic number.

It is an amenable number.

20105953251949 is a deficient number, since it is larger than the sum of its proper divisors (1).

20105953251949 is an equidigital number, since it uses as much as digits as its factorization.

20105953251949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4374000, while the sum is 55.

The spelling of 20105953251949 in words is "twenty trillion, one hundred five billion, nine hundred fifty-three million, two hundred fifty-one thousand, nine hundred forty-nine".