21000023100013 has 2 divisors, whose sum is σ = 21000023100014. Its totient is φ = 21000023100012.

The previous prime is 21000023099989. The next prime is 21000023100083. The reversal of 21000023100013 is 31000132000012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20097091748484 + 902931351529 = 4482978^2 + 950227^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000023100013 - 2⁵ = 21000023099981 is a prime.

It is a super-2 number, since 2×21000023100013² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21000023099966 and 21000023100002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000023100083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500011550006 + 10500011550007.

It is an arithmetic number, because the mean of its divisors is an integer number (10500011550007).

Almost surely, 2^{21000023100013} is an apocalyptic number.

It is an amenable number.

21000023100013 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000023100013 is an equidigital number, since it uses as much as digits as its factorization.

21000023100013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 13.

Adding to 21000023100013 its reverse (31000132000012), we get a palindrome (52000155100025).

The spelling of 21000023100013 in words is "twenty-one trillion, twenty-three million, one hundred thousand, thirteen".