21121271730 has 96 divisors (see below), whose sum is σ = 59888424960. Its totient is φ = 5133248640.

The previous prime is 21121271723. The next prime is 21121271753. The reversal of 21121271730 is 3717212112.

It is a super-2 number, since 2×21121271730² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121271694 and 21121271703.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21826 + ... + 206685.

It is an arithmetic number, because the mean of its divisors is an integer number (623837760).

Almost surely, 2^21121271730 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21121271730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29944212480).

21121271730 is an abundant number, since it is smaller than the sum of its proper divisors (38767153230).

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

21121271730 is a wasteful number, since it uses less digits than its factorization.

21121271730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228616 (or 228613 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 27.

Adding to 21121271730 its reverse (3717212112), we get a palindrome (24838483842).

The spelling of 21121271730 in words is "twenty-one billion, one hundred twenty-one million, two hundred seventy-one thousand, seven hundred thirty".