21021344455 has 8 divisors (see below), whose sum is σ = 25315385904. Its totient is φ = 16757227200.

The previous prime is 21021344447. The next prime is 21021344459. The reversal of 21021344455 is 55444312012.

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

It is not a de Polignac number, because 21021344455 - 2³ = 21021344447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021344459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7479501 + ... + 7482310.

It is an arithmetic number, because the mean of its divisors is an integer number (3164423238).

Almost surely, 2^21021344455 is an apocalyptic number.

21021344455 is a deficient number, since it is larger than the sum of its proper divisors (4294041449).

21021344455 is a wasteful number, since it uses less digits than its factorization.

21021344455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14962097.

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

Adding to 21021344455 its reverse (55444312012), we get a palindrome (76465656467).

The spelling of 21021344455 in words is "twenty-one billion, twenty-one million, three hundred forty-four thousand, four hundred fifty-five".