21221002012120 has 32 divisors (see below), whose sum is σ = 47747385900000. Its totient is φ = 8488377449728.

The previous prime is 21221002012099. The next prime is 21221002012129. The reversal of 21221002012120 is 2121020012212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21221002012094 and 21221002012103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221002012129) 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, 26949756 + ... + 27726004.

It is an arithmetic number, because the mean of its divisors is an integer number (1492105809375).

Almost surely, 2^{21221002012120} is an apocalyptic number.

21221002012120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221002012120 is an abundant number, since it is smaller than the sum of its proper divisors (26526383887880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221002012120 is a wasteful number, since it uses less digits than its factorization.

21221002012120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1459707 (or 1459703 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21221002012120 its reverse (2121020012212), we get a palindrome (23342022024332).

The spelling of 21221002012120 in words is "twenty-one trillion, two hundred twenty-one billion, two million, twelve thousand, one hundred twenty".