21021212202120 has 384 divisors, whose sum is σ = 76274494732800. Its totient is φ = 4985309693952.

The previous prime is 21021212202103. The next prime is 21021212202143. The reversal of 21021212202120 is 2120221212012.

It is a happy number.

21021212202120 is a `hidden beast` number, since 21 + 0 + 212 + 1 + 220 + 212 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21021212202093 and 21021212202102.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 63215409 + ... + 63547071.

It is an arithmetic number, because the mean of its divisors is an integer number (198631496700).

Almost surely, 2^{21021212202120} is an apocalyptic number.

21021212202120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021212202120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38137247366400).

21021212202120 is an abundant number, since it is smaller than the sum of its proper divisors (55253282530680).

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

21021212202120 is a wasteful number, since it uses less digits than its factorization.

21021212202120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332189 (or 332182 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21021212202120 its reverse (2120221212012), we get a palindrome (23141433414132).

The spelling of 21021212202120 in words is "twenty-one trillion, twenty-one billion, two hundred twelve million, two hundred two thousand, one hundred twenty".