21211211000 has 128 divisors (see below), whose sum is σ = 57013632000. Its totient is φ = 7235395200.

The previous prime is 21211210973. The next prime is 21211211017. The reversal of 21211211000 is 11211212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1385387 + ... + 1400613.

It is an arithmetic number, because the mean of its divisors is an integer number (445419000).

Almost surely, 2^21211211000 is an apocalyptic number.

21211211000 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 21211211000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28506816000).

21211211000 is an abundant number, since it is smaller than the sum of its proper divisors (35802421000).

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

21211211000 is a wasteful number, since it uses less digits than its factorization.

21211211000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15454 (or 15440 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21211211000 its reverse (11211212), we get a palindrome (21222422212).

It can be divided in two parts, 2121 and 1211000, that added together give a palindrome (1213121).

The spelling of 21211211000 in words is "twenty-one billion, two hundred eleven million, two hundred eleven thousand".