21120011212121 has 8 divisors (see below), whose sum is σ = 22362605520840. Its totient is φ = 19877443648768.

The previous prime is 21120011212109. The next prime is 21120011212133. The reversal of 21120011212121 is 12121211002112.

It is an interprime number because it is at equal distance from previous prime (21120011212109) and next prime (21120011212133).

It can be written as a sum of positive squares in 4 ways, for example, as 8199861331600 + 12920149880521 = 2863540^2 + 3594461^2 .

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

It is not a de Polignac number, because 21120011212121 - 2¹⁰ = 21120011211097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

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 21120011212121.

It is not an unprimeable number, because it can be changed into a prime (21120011212021) 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, 5049086 + ... + 8230023.

It is an arithmetic number, because the mean of its divisors is an integer number (2795325690105).

Almost surely, 2^{21120011212121} is an apocalyptic number.

It is an amenable number.

21120011212121 is a deficient number, since it is larger than the sum of its proper divisors (1242594308719).

21120011212121 is a wasteful number, since it uses less digits than its factorization.

21120011212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13372683.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21120011212121 its reverse (12121211002112), we get a palindrome (33241222214233).

The spelling of 21120011212121 in words is "twenty-one trillion, one hundred twenty billion, eleven million, two hundred twelve thousand, one hundred twenty-one".