18851322121 has 2 divisors, whose sum is σ = 18851322122. Its totient is φ = 18851322120.

The previous prime is 18851322103. The next prime is 18851322173. The reversal of 18851322121 is 12122315881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15360875721 + 3490446400 = 123939^2 + 59080^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18851322121 is a prime.

It is not a weakly prime, because it can be changed into another prime (18851322101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9425661060 + 9425661061.

It is an arithmetic number, because the mean of its divisors is an integer number (9425661061).

Almost surely, 2^18851322121 is an apocalyptic number.

It is an amenable number.

18851322121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18851322121 is an equidigital number, since it uses as much as digits as its factorization.

18851322121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7680, while the sum is 34.

The spelling of 18851322121 in words is "eighteen billion, eight hundred fifty-one million, three hundred twenty-two thousand, one hundred twenty-one".