21121210000 has 200 divisors, whose sum is σ = 56186564544. Its totient is φ = 7625280000.

The previous prime is 21121209979. The next prime is 21121210003. The reversal of 21121210000 is 1212112.

It is a tau number, because it is divible by the number of its divisors (200).

It is a super-2 number, since 2×21121210000² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121210003) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 17269389 + ... + 17270611.

Almost surely, 2^21121210000 is an apocalyptic number.

21121210000 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 21121210000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28093282272).

21121210000 is an abundant number, since it is smaller than the sum of its proper divisors (35065354544).

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

21121210000 is a wasteful number, since it uses less digits than its factorization.

21121210000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1419 (or 1398 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21121210000 its reverse (1212112), we get a palindrome (21122422112).

The spelling of 21121210000 in words is "twenty-one billion, one hundred twenty-one million, two hundred ten thousand".