21122121000 has 256 divisors, whose sum is σ = 68840928000. Its totient is φ = 5385139200.

The previous prime is 21122120993. The next prime is 21122121017. The reversal of 21122121000 is 12122112.

It is a super-2 number, since 2×21122121000² (a number of 21 digits) contains 22 as substring.

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, 9307866 + ... + 9310134.

It is an arithmetic number, because the mean of its divisors is an integer number (268909875).

Almost surely, 2^21122121000 is an apocalyptic number.

21122121000 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 21122121000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34420464000).

21122121000 is an abundant number, since it is smaller than the sum of its proper divisors (47718807000).

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

21122121000 is a wasteful number, since it uses less digits than its factorization.

21122121000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2429 (or 2415 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21122121000 its reverse (12122112), we get a palindrome (21134243112).

It can be divided in two parts, 211221 and 21000, that added together give a triangular number (232221 = T₆₈₁).

The spelling of 21122121000 in words is "twenty-one billion, one hundred twenty-two million, one hundred twenty-one thousand".