20549992121 has 2 divisors, whose sum is σ = 20549992122. Its totient is φ = 20549992120.

The previous prime is 20549992087. The next prime is 20549992147. The reversal of 20549992121 is 12129994502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20540622400 + 9369721 = 143320^2 + 3061^2 .

It is a cyclic number.

It is not a de Polignac number, because 20549992121 - 2¹⁰ = 20549991097 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20549992181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10274996060 + 10274996061.

It is an arithmetic number, because the mean of its divisors is an integer number (10274996061).

Almost surely, 2^20549992121 is an apocalyptic number.

It is an amenable number.

20549992121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20549992121 is an equidigital number, since it uses as much as digits as its factorization.

20549992121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 44.

The spelling of 20549992121 in words is "twenty billion, five hundred forty-nine million, nine hundred ninety-two thousand, one hundred twenty-one".