21121102109999 has 4 divisors (see below), whose sum is σ = 21159714728664. Its totient is φ = 21082489491336.

The previous prime is 21121102109963. The next prime is 21121102110007. The reversal of 21121102109999 is 99990120112112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21121102109999 - 2¹² = 21121102105903 is a prime.

It is a super-2 number, since 2×21121102109999² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121102109599) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19306308512 + ... + 19306309605.

It is an arithmetic number, because the mean of its divisors is an integer number (5289928682166).

Almost surely, 2^{21121102109999} is an apocalyptic number.

21121102109999 is a deficient number, since it is larger than the sum of its proper divisors (38612618665).

21121102109999 is an equidigital number, since it uses as much as digits as its factorization.

21121102109999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38612618664.

The product of its (nonzero) digits is 52488, while the sum is 47.

The spelling of 21121102109999 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred two million, one hundred nine thousand, nine hundred ninety-nine".