21516061512 has 256 divisors, whose sum is σ = 61719563520. Its totient is φ = 6193152000.

The previous prime is 21516061507. The next prime is 21516061513.

21516061512 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×21516061512² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21516061512.

It is not an unprimeable number, because it can be changed into a prime (21516061513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 111482088 + ... + 111482280.

It is an arithmetic number, because the mean of its divisors is an integer number (241092045).

Almost surely, 2^21516061512 is an apocalyptic number.

21516061512 is a gapful number since it is divisible by the number (22) 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 21516061512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30859781760).

21516061512 is an abundant number, since it is smaller than the sum of its proper divisors (40203502008).

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

21516061512 is a wasteful number, since it uses less digits than its factorization.

21516061512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464 (or 460 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 30.

It can be divided in two parts, 215160 and 61512, that added together give a palindrome (276672).

The spelling of 21516061512 in words is "twenty-one billion, five hundred sixteen million, sixty-one thousand, five hundred twelve".