21321340653 has 16 divisors (see below), whose sum is σ = 31409444736. Its totient is φ = 12796439040.

The previous prime is 21321340631. The next prime is 21321340661. The reversal of 21321340653 is 35604312312.

It is not a de Polignac number, because 21321340653 - 2¹⁰ = 21321339629 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21321340653.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321340603) 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 15 ways as a sum of consecutive naturals, for example, 9087208 + ... + 9089553.

It is an arithmetic number, because the mean of its divisors is an integer number (1963090296).

Almost surely, 2^21321340653 is an apocalyptic number.

21321340653 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21321340653 is a deficient number, since it is larger than the sum of its proper divisors (10088104083).

21321340653 is a wasteful number, since it uses less digits than its factorization.

21321340653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18176804.

The product of its (nonzero) digits is 12960, while the sum is 30.

Adding to 21321340653 its reverse (35604312312), we get a palindrome (56925652965).

The spelling of 21321340653 in words is "twenty-one billion, three hundred twenty-one million, three hundred forty thousand, six hundred fifty-three".