21011210221221 has 24 divisors (see below), whose sum is σ = 33916099875840. Its totient is φ = 12423479803200.

The previous prime is 21011210221207. The next prime is 21011210221231. The reversal of 21011210221221 is 12212201211012.

21011210221221 is a `hidden beast` number, since 2 + 1 + 0 + 11 + 210 + 221 + 221 = 666.

It is not a de Polignac number, because 21011210221221 - 2¹¹ = 21011210219173 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21011210221194 and 21011210221203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011210221231) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2588220901 + ... + 2588229018.

It is an arithmetic number, because the mean of its divisors is an integer number (1413170828160).

Almost surely, 2^{21011210221221} is an apocalyptic number.

It is an amenable number.

21011210221221 is a deficient number, since it is larger than the sum of its proper divisors (12904889654619).

21011210221221 is a wasteful number, since it uses less digits than its factorization.

21011210221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5176449977 (or 5176449974 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21011210221221 its reverse (12212201211012), we get a palindrome (33223411432233).

The spelling of 21011210221221 in words is "twenty-one trillion, eleven billion, two hundred ten million, two hundred twenty-one thousand, two hundred twenty-one".