21311121000 has 256 divisors, whose sum is σ = 72024825600. Its totient is φ = 5215104000.

The previous prime is 21311120981. The next prime is 21311121043. The reversal of 21311121000 is 12111312.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7057491 + ... + 7060509.

It is an arithmetic number, because the mean of its divisors is an integer number (281346975).

Almost surely, 2^21311121000 is an apocalyptic number.

21311121000 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 21311121000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36012412800).

21311121000 is an abundant number, since it is smaller than the sum of its proper divisors (50713704600).

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

21311121000 is a wasteful number, since it uses less digits than its factorization.

21311121000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3237 (or 3223 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 12.

Adding to 21311121000 its reverse (12111312), we get a palindrome (21323232312).

It can be divided in two parts, 21311 and 121000, that added together give a triangular number (142311 = T₅₃₃).

The spelling of 21311121000 in words is "twenty-one billion, three hundred eleven million, one hundred twenty-one thousand".