21909524450 has 90 divisors (see below), whose sum is σ = 45087219795. Its totient is φ = 7921047200.

The previous prime is 21909524411. The next prime is 21909524453. The reversal of 21909524450 is 5442590912.

It can be written as a sum of positive squares in 5 ways, for example, as 17812372369 + 4097152081 = 133463^2 + 64009^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=104665.

It is a junction number, because it is equal to n+sod(n) for n = 21909524398 and 21909524407.

It is not an unprimeable number, because it can be changed into a prime (21909524453) 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 44 ways as a sum of consecutive naturals, for example, 126644564 + ... + 126644736.

Almost surely, 2^21909524450 is an apocalyptic number.

21909524450 is an abundant number, since it is smaller than the sum of its proper divisors (23177695345).

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

21909524450 is an frugal number, since it uses more digits than its factorization.

21909524450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 41.

The spelling of 21909524450 in words is "twenty-one billion, nine hundred nine million, five hundred twenty-four thousand, four hundred fifty".