21145324243264 has 28 divisors (see below), whose sum is σ = 45187964550484. Its totient is φ = 9759380419584.

The previous prime is 21145324243261. The next prime is 21145324243363. The reversal of 21145324243264 is 46234242354112.

It can be written as a sum of positive squares in 2 ways, for example, as 4353031577664 + 16792292665600 = 2086392^2 + 4097840^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21145324243264.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145324243261) 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 3 ways as a sum of consecutive naturals, for example, 12707525757 + ... + 12707527420.

It is an arithmetic number, because the mean of its divisors is an integer number (1613855876803).

Almost surely, 2^{21145324243264} is an apocalyptic number.

It is an amenable number.

21145324243264 is an abundant number, since it is smaller than the sum of its proper divisors (24042640307220).

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

21145324243264 is a wasteful number, since it uses less digits than its factorization.

21145324243264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25415053202 (or 25415053192 counting only the distinct ones).

The product of its digits is 1105920, while the sum is 43.

Adding to 21145324243264 its reverse (46234242354112), we get a palindrome (67379566597376).

The spelling of 21145324243264 in words is "twenty-one trillion, one hundred forty-five billion, three hundred twenty-four million, two hundred forty-three thousand, two hundred sixty-four".