21204354525064 has 16 divisors (see below), whose sum is σ = 39760183518300. Its totient is φ = 10601638920192.

The previous prime is 21204354525017. The next prime is 21204354525091. The reversal of 21204354525064 is 46052545340212.

It can be written as a sum of positive squares in 2 ways, for example, as 18369367402500 + 2834987122564 = 4285950^2 + 1683742^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21204354525064.

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 3 ways as a sum of consecutive naturals, for example, 67125369 + ... + 67440520.

Almost surely, 2^{21204354525064} is an apocalyptic number.

It is an amenable number.

21204354525064 is a deficient number, since it is larger than the sum of its proper divisors (18555828993236).

21204354525064 is a wasteful number, since it uses less digits than its factorization.

21204354525064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134585592 (or 134585588 counting only the distinct ones).

The product of its (nonzero) digits is 1152000, while the sum is 43.

Adding to 21204354525064 its reverse (46052545340212), we get a palindrome (67256899865276).

The spelling of 21204354525064 in words is "twenty-one trillion, two hundred four billion, three hundred fifty-four million, five hundred twenty-five thousand, sixty-four".