21864139450 has 24 divisors (see below), whose sum is σ = 43059495132. Its totient is φ = 8231205120.

The previous prime is 21864139441. The next prime is 21864139469. The reversal of 21864139450 is 5493146812.

It can be written as a sum of positive squares in 6 ways, for example, as 7911568809 + 13952570641 = 88947^2 + 118121^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21864139397 and 21864139406.

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 11 ways as a sum of consecutive naturals, for example, 12860409 + ... + 12862108.

Almost surely, 2^21864139450 is an apocalyptic number.

21864139450 is a deficient number, since it is larger than the sum of its proper divisors (21195355682).

21864139450 is a wasteful number, since it uses less digits than its factorization.

21864139450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25722546 (or 25722541 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 43.

The spelling of 21864139450 in words is "twenty-one billion, eight hundred sixty-four million, one hundred thirty-nine thousand, four hundred fifty".