21011220020121 has 8 divisors (see below), whose sum is σ = 28016180123040. Its totient is φ = 14006869965312.

The previous prime is 21011220020113. The next prime is 21011220020173. The reversal of 21011220020121 is 12102002211012.

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

It is not a de Polignac number, because 21011220020121 - 2³ = 21011220020113 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21011220020121.

It is not an unprimeable number, because it can be changed into a prime (21011220020521) 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, 152431656 + ... + 152569433.

It is an arithmetic number, because the mean of its divisors is an integer number (3502022515380).

Almost surely, 2^{21011220020121} is an apocalyptic number.

It is an amenable number.

21011220020121 is a deficient number, since it is larger than the sum of its proper divisors (7004960102919).

21011220020121 is a wasteful number, since it uses less digits than its factorization.

21011220020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305024055.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21011220020121 its reverse (12102002211012), we get a palindrome (33113222231133).

The spelling of 21011220020121 in words is "twenty-one trillion, eleven billion, two hundred twenty million, twenty thousand, one hundred twenty-one".