21121203330 has 128 divisors (see below), whose sum is σ = 56723293440. Its totient is φ = 5592499200.

The previous prime is 21121203293. The next prime is 21121203331. The reversal of 21121203330 is 3330212112.

21121203330 is a `hidden beast` number, since 211 + 2 + 120 + 3 + 330 = 666.

It is a super-2 number, since 2×21121203330² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21121203331) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 40384449 + ... + 40384971.

It is an arithmetic number, because the mean of its divisors is an integer number (443150730).

Almost surely, 2^21121203330 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21121203330, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28361646720).

21121203330 is an abundant number, since it is smaller than the sum of its proper divisors (35602090110).

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

21121203330 is a wasteful number, since it uses less digits than its factorization.

21121203330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1313 (or 1307 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

Adding to 21121203330 its reverse (3330212112), we get a palindrome (24451415442).

The spelling of 21121203330 in words is "twenty-one billion, one hundred twenty-one million, two hundred three thousand, three hundred thirty".