21011211221000 has 768 divisors, whose sum is σ = 68044543257600. Its totient is φ = 5968505088000.

The previous prime is 21011211220957. The next prime is 21011211221003. The reversal of 21011211221000 is 12211211012.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is not an unprimeable number, because it can be changed into a prime (21011211221003) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 553534022 + ... + 553571978.

It is an arithmetic number, because the mean of its divisors is an integer number (88599665700).

Almost surely, 2^{21011211221000} is an apocalyptic number.

21011211221000 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 21011211221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34022271628800).

21011211221000 is an abundant number, since it is smaller than the sum of its proper divisors (47033332036600).

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

21011211221000 is a wasteful number, since it uses less digits than its factorization.

21011211221000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38095 (or 38074 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21011211221000 its reverse (12211211012), we get a palindrome (21023422432012).

The spelling of 21011211221000 in words is "twenty-one trillion, eleven billion, two hundred eleven million, two hundred twenty-one thousand".