21011110202121 has 32 divisors (see below), whose sum is σ = 31483074954240. Its totient is φ = 12367136721984.

The previous prime is 21011110202113. The next prime is 21011110202141. The reversal of 21011110202121 is 12120201111012.

It is a happy number.

It is not a de Polignac number, because 21011110202121 - 2³ = 21011110202113 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21011110202121.

It is not an unprimeable number, because it can be changed into a prime (21011110202141) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18045550 + ... + 19174568.

It is an arithmetic number, because the mean of its divisors is an integer number (983846092320).

Almost surely, 2^{21011110202121} is an apocalyptic number.

It is an amenable number.

21011110202121 is a deficient number, since it is larger than the sum of its proper divisors (10471964752119).

21011110202121 is a wasteful number, since it uses less digits than its factorization.

21011110202121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1149805.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21011110202121 its reverse (12120201111012), we get a palindrome (33131311313133).

The spelling of 21011110202121 in words is "twenty-one trillion, eleven billion, one hundred ten million, two hundred two thousand, one hundred twenty-one".