21121332351504 has 320 divisors, whose sum is σ = 69553719705600. Its totient is φ = 5363215925760.

The previous prime is 21121332351487. The next prime is 21121332351521. The reversal of 21121332351504 is 40515323312112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21121332351487) and next prime (21121332351521).

It is a super-2 number, since 2×21121332351504² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 153318847 + ... + 153456545.

It is an arithmetic number, because the mean of its divisors is an integer number (217355374080).

Almost surely, 2^{21121332351504} is an apocalyptic number.

21121332351504 is a gapful number since it is divisible by the number (24) 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 21121332351504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34776859852800).

21121332351504 is an abundant number, since it is smaller than the sum of its proper divisors (48432387354096).

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

21121332351504 is a wasteful number, since it uses less digits than its factorization.

21121332351504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138658 (or 138652 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 33.

Adding to 21121332351504 its reverse (40515323312112), we get a palindrome (61636655663616).

The spelling of 21121332351504 in words is "twenty-one trillion, one hundred twenty-one billion, three hundred thirty-two million, three hundred fifty-one thousand, five hundred four".