21040045005 has 64 divisors (see below), whose sum is σ = 39655715328. Its totient is φ = 9324564480.

The previous prime is 21040045001. The next prime is 21040045007. The reversal of 21040045005 is 50054004012.

It is not a de Polignac number, because 21040045005 - 2² = 21040045001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040045001) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 1082049 + ... + 1101321.

It is an arithmetic number, because the mean of its divisors is an integer number (619620552).

Almost surely, 2^21040045005 is an apocalyptic number.

It is an amenable number.

21040045005 is a deficient number, since it is larger than the sum of its proper divisors (18615670323).

21040045005 is a wasteful number, since it uses less digits than its factorization.

21040045005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19606.

The product of its (nonzero) digits is 800, while the sum is 21.

Adding to 21040045005 its reverse (50054004012), we get a palindrome (71094049017).

The spelling of 21040045005 in words is "twenty-one billion, forty million, forty-five thousand, five".