21621343335065 has 8 divisors (see below), whose sum is σ = 25945698749568. Its totient is φ = 17297016836400.

The previous prime is 21621343335061. The next prime is 21621343335077. The reversal of 21621343335065 is 56053334312612.

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

It is not a de Polignac number, because 21621343335065 - 2² = 21621343335061 is a prime.

It is a super-2 number, since 2×21621343335065² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621343335061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5548427 + ... + 8603936.

It is an arithmetic number, because the mean of its divisors is an integer number (3243212343696).

Almost surely, 2^{21621343335065} is an apocalyptic number.

It is an amenable number.

21621343335065 is a deficient number, since it is larger than the sum of its proper divisors (4324355414503).

21621343335065 is a wasteful number, since it uses less digits than its factorization.

21621343335065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14457919.

The product of its (nonzero) digits is 1166400, while the sum is 44.

Adding to 21621343335065 its reverse (56053334312612), we get a palindrome (77674677647677).

The spelling of 21621343335065 in words is "twenty-one trillion, six hundred twenty-one billion, three hundred forty-three million, three hundred thirty-five thousand, sixty-five".