21816687312 has 80 divisors (see below), whose sum is σ = 71567978880. Its totient is φ = 6233338368.

The previous prime is 21816687301. The next prime is 21816687331. The reversal of 21816687312 is 21378661812.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 3604233 + ... + 3610280.

It is an arithmetic number, because the mean of its divisors is an integer number (894599736).

Almost surely, 2^21816687312 is an apocalyptic number.

It is an amenable number.

21816687312 is an abundant number, since it is smaller than the sum of its proper divisors (49751291568).

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

21816687312 is a wasteful number, since it uses less digits than its factorization.

21816687312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7214537 (or 7214525 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The spelling of 21816687312 in words is "twenty-one billion, eight hundred sixteen million, six hundred eighty-seven thousand, three hundred twelve".