21100100011873 has 2 divisors, whose sum is σ = 21100100011874. Its totient is φ = 21100100011872.

The previous prime is 21100100011871. The next prime is 21100100011877. The reversal of 21100100011873 is 37811000100112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20775938311969 + 324161699904 = 4558063^2 + 569352^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100100011873 - 2¹ = 21100100011871 is a prime.

It is a super-2 number, since 2×21100100011873² (a number of 27 digits) contains 22 as substring.

Together with 21100100011871, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21100100011871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550050005936 + 10550050005937.

It is an arithmetic number, because the mean of its divisors is an integer number (10550050005937).

Almost surely, 2^{21100100011873} is an apocalyptic number.

It is an amenable number.

21100100011873 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100100011873 is an equidigital number, since it uses as much as digits as its factorization.

21100100011873 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 25.

Adding to 21100100011873 its reverse (37811000100112), we get a palindrome (58911100111985).

The spelling of 21100100011873 in words is "twenty-one trillion, one hundred billion, one hundred million, eleven thousand, eight hundred seventy-three".