21121001111121 has 8 divisors (see below), whose sum is σ = 28164453838080. Its totient is φ = 14079107895792.

The previous prime is 21121001111117. The next prime is 21121001111123. The reversal of 21121001111121 is 12111110012112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21121001111121 - 2² = 21121001111117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21121001111121.

It is not an unprimeable number, because it can be changed into a prime (21121001111123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389846305 + ... + 389900478.

It is an arithmetic number, because the mean of its divisors is an integer number (3520556729760).

Almost surely, 2^{21121001111121} is an apocalyptic number.

It is an amenable number.

21121001111121 is a deficient number, since it is larger than the sum of its proper divisors (7043452726959).

21121001111121 is an equidigital number, since it uses as much as digits as its factorization.

21121001111121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 779755815.

The product of its (nonzero) digits is 8, while the sum is 15.

Adding to 21121001111121 its reverse (12111110012112), we get a palindrome (33232111123233).

The spelling of 21121001111121 in words is "twenty-one trillion, one hundred twenty-one billion, one million, one hundred eleven thousand, one hundred twenty-one".