21165246464 has 48 divisors (see below), whose sum is σ = 42474077100. Its totient is φ = 10544136192.

The previous prime is 21165246451. The next prime is 21165246481. The reversal of 21165246464 is 46464256112.

It can be written as a sum of positive squares in 2 ways, for example, as 20451288064 + 713958400 = 143008^2 + 26720^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 548642 + ... + 585950.

Almost surely, 2^21165246464 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21165246464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21237038550).

21165246464 is an abundant number, since it is smaller than the sum of its proper divisors (21308830636).

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

21165246464 is an equidigital number, since it uses as much as digits as its factorization.

21165246464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37608 (or 37588 counting only the distinct ones).

The product of its digits is 276480, while the sum is 41.

The spelling of 21165246464 in words is "twenty-one billion, one hundred sixty-five million, two hundred forty-six thousand, four hundred sixty-four".