21005345055 has 8 divisors (see below), whose sum is σ = 33608552112. Its totient is φ = 11202850688.

The previous prime is 21005345041. The next prime is 21005345077. The reversal of 21005345055 is 55054350012.

It is a happy number.

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 21005345055 - 2⁶ = 21005344991 is a prime.

It is a super-2 number, since 2×21005345055² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 700178154 + ... + 700178183.

It is an arithmetic number, because the mean of its divisors is an integer number (4201069014).

Almost surely, 2^21005345055 is an apocalyptic number.

21005345055 is a deficient number, since it is larger than the sum of its proper divisors (12603207057).

21005345055 is a wasteful number, since it uses less digits than its factorization.

21005345055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1400356345.

The product of its (nonzero) digits is 15000, while the sum is 30.

Adding to 21005345055 its reverse (55054350012), we get a palindrome (76059695067).

The spelling of 21005345055 in words is "twenty-one billion, five million, three hundred forty-five thousand, fifty-five".