21385318280 has 16 divisors (see below), whose sum is σ = 48116966220. Its totient is φ = 8554127296.

The previous prime is 21385318259. The next prime is 21385318309. The reversal of 21385318280 is 8281358312.

It can be written as a sum of positive squares in 2 ways, for example, as 19785798244 + 1599520036 = 140662^2 + 39994^2 .

It is an unprimeable number.

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, 267316439 + ... + 267316518.

Almost surely, 2^21385318280 is an apocalyptic number.

21385318280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21385318280 is an abundant number, since it is smaller than the sum of its proper divisors (26731647940).

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

21385318280 is a wasteful number, since it uses less digits than its factorization.

21385318280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 534632968 (or 534632964 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 41.

The spelling of 21385318280 in words is "twenty-one billion, three hundred eighty-five million, three hundred eighteen thousand, two hundred eighty".