21144320455 has 8 divisors (see below), whose sum is σ = 25376622912. Its totient is φ = 16913164128.

The previous prime is 21144320437. The next prime is 21144320489. The reversal of 21144320455 is 55402344112.

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 21144320455 - 2⁹ = 21144319943 is a prime.

It is a Duffinian number.

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 in 7 ways as a sum of consecutive naturals, for example, 245407 + ... + 320176.

It is an arithmetic number, because the mean of its divisors is an integer number (3172077864).

Almost surely, 2^21144320455 is an apocalyptic number.

21144320455 is a deficient number, since it is larger than the sum of its proper divisors (4232302457).

21144320455 is an equidigital number, since it uses as much as digits as its factorization.

21144320455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573065.

The product of its (nonzero) digits is 19200, while the sum is 31.

Adding to 21144320455 its reverse (55402344112), we get a palindrome (76546664567).

The spelling of 21144320455 in words is "twenty-one billion, one hundred forty-four million, three hundred twenty thousand, four hundred fifty-five".