21645541364 has 6 divisors (see below), whose sum is σ = 37879697394. Its totient is φ = 10822770680.

The previous prime is 21645541343. The next prime is 21645541381. The reversal of 21645541364 is 46314554612.

It can be written as a sum of positive squares in only one way, i.e., 17168860900 + 4476680464 = 131030^2 + 66908^2 .

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2705692667 + ... + 2705692674.

It is an arithmetic number, because the mean of its divisors is an integer number (6313282899).

Almost surely, 2^21645541364 is an apocalyptic number.

It is an amenable number.

21645541364 is a deficient number, since it is larger than the sum of its proper divisors (16234156030).

21645541364 is a wasteful number, since it uses less digits than its factorization.

21645541364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5411385345 (or 5411385343 counting only the distinct ones).

The product of its digits is 345600, while the sum is 41.

The spelling of 21645541364 in words is "twenty-one billion, six hundred forty-five million, five hundred forty-one thousand, three hundred sixty-four".