21111011212121 has 8 divisors (see below), whose sum is σ = 21113616902400. Its totient is φ = 21108405714048.

The previous prime is 21111011212103. The next prime is 21111011212127. The reversal of 21111011212121 is 12121211011112.

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

It is a cyclic number.

It is not a de Polignac number, because 21111011212121 - 2¹⁰ = 21111011211097 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21111011212121.

It is not an unprimeable number, because it can be changed into a prime (21111011212127) 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, 372057065 + ... + 372113801.

It is an arithmetic number, because the mean of its divisors is an integer number (2639202112800).

Almost surely, 2^{21111011212121} is an apocalyptic number.

It is an amenable number.

21111011212121 is a deficient number, since it is larger than the sum of its proper divisors (2605690279).

21111011212121 is a wasteful number, since it uses less digits than its factorization.

21111011212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96103.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 21111011212121 its reverse (12121211011112), we get a palindrome (33232222223233).

The spelling of 21111011212121 in words is "twenty-one trillion, one hundred eleven billion, eleven million, two hundred twelve thousand, one hundred twenty-one".