21211220121000 has 512 divisors, whose sum is σ = 81477397048320. Its totient is φ = 4473888768000.

The previous prime is 21211220120983. The next prime is 21211220121043. The reversal of 21211220121000 is 12102211212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 987430260 + ... + 987451740.

It is an arithmetic number, because the mean of its divisors is an integer number (159135541110).

Almost surely, 2^{21211220121000} is an apocalyptic number.

21211220121000 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 21211220121000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40738698524160).

21211220121000 is an abundant number, since it is smaller than the sum of its proper divisors (60266176927320).

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

21211220121000 is a wasteful number, since it uses less digits than its factorization.

21211220121000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25142 (or 25128 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21211220121000 its reverse (12102211212), we get a palindrome (21223322332212).

The spelling of 21211220121000 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty million, one hundred twenty-one thousand".