23121021997 has 2 divisors, whose sum is σ = 23121021998. Its totient is φ = 23121021996.

The previous prime is 23121021971. The next prime is 23121022061. The reversal of 23121021997 is 79912012132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13938399721 + 9182622276 = 118061^2 + 95826^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23121021997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23121091997) 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, 11560510998 + 11560510999.

It is an arithmetic number, because the mean of its divisors is an integer number (11560510999).

Almost surely, 2^23121021997 is an apocalyptic number.

It is an amenable number.

23121021997 is a deficient number, since it is larger than the sum of its proper divisors (1).

23121021997 is an equidigital number, since it uses as much as digits as its factorization.

23121021997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 37.

The spelling of 23121021997 in words is "twenty-three billion, one hundred twenty-one million, twenty-one thousand, nine hundred ninety-seven".