20100121997 has 2 divisors, whose sum is σ = 20100121998. Its totient is φ = 20100121996.

The previous prime is 20100121969. The next prime is 20100122051. The reversal of 20100121997 is 79912100102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18492192196 + 1607929801 = 135986^2 + 40099^2 .

It is a cyclic number.

It is not a de Polignac number, because 20100121997 - 2¹⁶ = 20100056461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20100121597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050060998 + 10050060999.

It is an arithmetic number, because the mean of its divisors is an integer number (10050060999).

Almost surely, 2^20100121997 is an apocalyptic number.

It is an amenable number.

20100121997 is a deficient number, since it is larger than the sum of its proper divisors (1).

20100121997 is an equidigital number, since it uses as much as digits as its factorization.

20100121997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2268, while the sum is 32.

The spelling of 20100121997 in words is "twenty billion, one hundred million, one hundred twenty-one thousand, nine hundred ninety-seven".