21103000099981 has 2 divisors, whose sum is σ = 21103000099982. Its totient is φ = 21103000099980.

The previous prime is 21103000099943. The next prime is 21103000100099. The reversal of 21103000099981 is 18999000030112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20591583462025 + 511416637956 = 4537795^2 + 715134^2 .

It is a cyclic number.

It is not a de Polignac number, because 21103000099981 - 2⁹ = 21103000099469 is a prime.

It is a super-2 number, since 2×21103000099981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21103000099921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551500049990 + 10551500049991.

It is an arithmetic number, because the mean of its divisors is an integer number (10551500049991).

Almost surely, 2^{21103000099981} is an apocalyptic number.

It is an amenable number.

21103000099981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103000099981 is an equidigital number, since it uses as much as digits as its factorization.

21103000099981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 43.

The spelling of 21103000099981 in words is "twenty-one trillion, one hundred three billion, ninety-nine thousand, nine hundred eighty-one".