21210202120121 has 16 divisors (see below), whose sum is σ = 25024217530368. Its totient is φ = 17592279138000.

The previous prime is 21210202120091. The next prime is 21210202120147. The reversal of 21210202120121 is 12102120201212.

It is not a de Polignac number, because 21210202120121 - 2¹⁴ = 21210202103737 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210202120121.

It is not an unprimeable number, because it can be changed into a prime (21210202120181) 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, 1324205 + ... + 6646346.

It is an arithmetic number, because the mean of its divisors is an integer number (1564013595648).

Almost surely, 2^{21210202120121} is an apocalyptic number.

It is an amenable number.

21210202120121 is a deficient number, since it is larger than the sum of its proper divisors (3814015410247).

21210202120121 is a wasteful number, since it uses less digits than its factorization.

21210202120121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7982852.

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

Adding to 21210202120121 its reverse (12102120201212), we get a palindrome (33312322321333).

The spelling of 21210202120121 in words is "twenty-one trillion, two hundred ten billion, two hundred two million, one hundred twenty thousand, one hundred twenty-one".