21085284918 has 16 divisors (see below), whose sum is σ = 42330917376. Its totient is φ = 7001703720.

The previous prime is 21085284917. The next prime is 21085284919. The reversal of 21085284918 is 81948258012.

It is an interprime number because it is at equal distance from previous prime (21085284917) and next prime (21085284919).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21085284917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6679438 + ... + 6682593.

It is an arithmetic number, because the mean of its divisors is an integer number (2645682336).

Almost surely, 2^21085284918 is an apocalyptic number.

21085284918 is an abundant number, since it is smaller than the sum of its proper divisors (21245632458).

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

21085284918 is a wasteful number, since it uses less digits than its factorization.

21085284918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13362299.

The product of its (nonzero) digits is 368640, while the sum is 48.

The spelling of 21085284918 in words is "twenty-one billion, eighty-five million, two hundred eighty-four thousand, nine hundred eighteen".