21012212002121 has 16 divisors (see below), whose sum is σ = 23280510670848. Its totient is φ = 18876089664000.

The previous prime is 21012212002109. The next prime is 21012212002129. The reversal of 21012212002121 is 12120021221012.

It is a cyclic number.

It is not a de Polignac number, because 21012212002121 - 2¹⁰ = 21012212001097 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 21012212002121.

It is not an unprimeable number, because it can be changed into a prime (21012212002129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 273053105 + ... + 273130046.

It is an arithmetic number, because the mean of its divisors is an integer number (1455031916928).

Almost surely, 2^{21012212002121} is an apocalyptic number.

It is an amenable number.

21012212002121 is a deficient number, since it is larger than the sum of its proper divisors (2268298668727).

21012212002121 is a wasteful number, since it uses less digits than its factorization.

21012212002121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546183272.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21012212002121 its reverse (12120021221012), we get a palindrome (33132233223133).

The spelling of 21012212002121 in words is "twenty-one trillion, twelve billion, two hundred twelve million, two thousand, one hundred twenty-one".