20811805149745 has 16 divisors (see below), whose sum is σ = 25038405383040. Its totient is φ = 16606632701824.

The previous prime is 20811805149659. The next prime is 20811805149749. The reversal of 20811805149745 is 54794150811802.

It is a cyclic number.

It is not a de Polignac number, because 20811805149745 - 2³⁷ = 20674366196273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20811805149749) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10431684 + ... + 12265546.

It is an arithmetic number, because the mean of its divisors is an integer number (1564900336440).

Almost surely, 2^{20811805149745} is an apocalyptic number.

It is an amenable number.

20811805149745 is a deficient number, since it is larger than the sum of its proper divisors (4226600233295).

20811805149745 is a wasteful number, since it uses less digits than its factorization.

20811805149745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1839704.

The product of its (nonzero) digits is 3225600, while the sum is 55.

The spelling of 20811805149745 in words is "twenty trillion, eight hundred eleven billion, eight hundred five million, one hundred forty-nine thousand, seven hundred forty-five".