21305320545 has 8 divisors (see below), whose sum is σ = 34088512896. Its totient is φ = 11362837616.

The previous prime is 21305320541. The next prime is 21305320577. The reversal of 21305320545 is 54502350312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21305320545 - 2² = 21305320541 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21305320541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 710177337 + ... + 710177366.

It is an arithmetic number, because the mean of its divisors is an integer number (4261064112).

Almost surely, 2^21305320545 is an apocalyptic number.

It is an amenable number.

21305320545 is a deficient number, since it is larger than the sum of its proper divisors (12783192351).

21305320545 is a wasteful number, since it uses less digits than its factorization.

21305320545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1420354711.

The product of its (nonzero) digits is 18000, while the sum is 30.

Adding to 21305320545 its reverse (54502350312), we get a palindrome (75807670857).

The spelling of 21305320545 in words is "twenty-one billion, three hundred five million, three hundred twenty thousand, five hundred forty-five".