21648137536 has 14 divisors (see below), whose sum is σ = 42958023050. Its totient is φ = 10824068736.

The previous prime is 21648137509. The next prime is 21648137647. The reversal of 21648137536 is 63573184612.

It can be written as a sum of positive squares in only one way, i.e., 21609000000 + 39137536 = 147000^2 + 6256^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 169126011 + ... + 169126138.

Almost surely, 2^21648137536 is an apocalyptic number.

It is an amenable number.

21648137536 is a deficient number, since it is larger than the sum of its proper divisors (21309885514).

21648137536 is an equidigital number, since it uses as much as digits as its factorization.

21648137536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338252161 (or 338252151 counting only the distinct ones).

The product of its digits is 725760, while the sum is 46.

The spelling of 21648137536 in words is "twenty-one billion, six hundred forty-eight million, one hundred thirty-seven thousand, five hundred thirty-six".