21002112120221 has 16 divisors (see below), whose sum is σ = 22320949680000. Its totient is φ = 19692682114560.

The previous prime is 21002112120191. The next prime is 21002112120247. The reversal of 21002112120221 is 12202121120012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002112120221 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21002112120221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002112129221) 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, 2677280 + ... + 7012278.

It is an arithmetic number, because the mean of its divisors is an integer number (1395059355000).

Almost surely, 2^{21002112120221} is an apocalyptic number.

It is an amenable number.

21002112120221 is a deficient number, since it is larger than the sum of its proper divisors (1318837559779).

21002112120221 is a wasteful number, since it uses less digits than its factorization.

21002112120221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4336084.

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

Adding to 21002112120221 its reverse (12202121120012), we get a palindrome (33204233240233).

The spelling of 21002112120221 in words is "twenty-one trillion, two billion, one hundred twelve million, one hundred twenty thousand, two hundred twenty-one".