21084821356 has 12 divisors (see below), whose sum is σ = 36899662240. Its totient is φ = 10542060720.

The previous prime is 21084821339. The next prime is 21084821357. The reversal of 21084821356 is 65312848012.

It is a super-2 number, since 2×21084821356² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21084821357) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 86530 + ... + 222838.

Almost surely, 2^21084821356 is an apocalyptic number.

It is an amenable number.

21084821356 is a deficient number, since it is larger than the sum of its proper divisors (15814840884).

21084821356 is a wasteful number, since it uses less digits than its factorization.

21084821356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174984 (or 174982 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 40.

The spelling of 21084821356 in words is "twenty-one billion, eighty-four million, eight hundred twenty-one thousand, three hundred fifty-six".