10123720121 has 2 divisors, whose sum is σ = 10123720122. Its totient is φ = 10123720120.

The previous prime is 10123720091. The next prime is 10123720157. The reversal of 10123720121 is 12102732101.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9842822521 + 280897600 = 99211^2 + 16760^2 .

It is a cyclic number.

It is not a de Polignac number, because 10123720121 - 2²² = 10119525817 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 10123720093 and 10123720102.

It is not a weakly prime, because it can be changed into another prime (10123720921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5061860060 + 5061860061.

It is an arithmetic number, because the mean of its divisors is an integer number (5061860061).

Almost surely, 2^10123720121 is an apocalyptic number.

It is an amenable number.

10123720121 is a deficient number, since it is larger than the sum of its proper divisors (1).

10123720121 is an equidigital number, since it uses as much as digits as its factorization.

10123720121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 20.

The spelling of 10123720121 in words is "ten billion, one hundred twenty-three million, seven hundred twenty thousand, one hundred twenty-one".