21012120112221 has 64 divisors (see below), whose sum is σ = 36268414640640. Its totient is φ = 11773525271040.

The previous prime is 21012120112219. The next prime is 21012120112223. The reversal of 21012120112221 is 12221102121012.

21012120112221 is a `hidden beast` number, since 210 + 1 + 2 + 120 + 112 + 221 = 666.

It is an interprime number because it is at equal distance from previous prime (21012120112219) and next prime (21012120112223).

It is not a de Polignac number, because 21012120112221 - 2¹ = 21012120112219 is a prime.

It is a super-2 number, since 2×21012120112221² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21012120112194 and 21012120112203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012120112223) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16629831 + ... + 17848683.

It is an arithmetic number, because the mean of its divisors is an integer number (566693978760).

Almost surely, 2^{21012120112221} is an apocalyptic number.

21012120112221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21012120112221 is a deficient number, since it is larger than the sum of its proper divisors (15256294528419).

21012120112221 is a wasteful number, since it uses less digits than its factorization.

21012120112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1220643 (or 1220637 counting only the distinct ones).

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

Adding to 21012120112221 its reverse (12221102121012), we get a palindrome (33233222233233).

The spelling of 21012120112221 in words is "twenty-one trillion, twelve billion, one hundred twenty million, one hundred twelve thousand, two hundred twenty-one".