21016281216 has 128 divisors (see below), whose sum is σ = 67157452800. Its totient is φ = 5688603648.

The previous prime is 21016281203. The next prime is 21016281241. The reversal of 21016281216 is 61218261012.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×21016281216² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154680 + ... + 256823.

It is an arithmetic number, because the mean of its divisors is an integer number (524667600).

Almost surely, 2^21016281216 is an apocalyptic number.

It is an amenable number.

21016281216 is an abundant number, since it is smaller than the sum of its proper divisors (46141171584).

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

21016281216 is a wasteful number, since it uses less digits than its factorization.

21016281216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 411546 (or 411534 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The spelling of 21016281216 in words is "twenty-one billion, sixteen million, two hundred eighty-one thousand, two hundred sixteen".