21006438574 has 16 divisors (see below), whose sum is σ = 34376420736. Its totient is φ = 9547756600.

The previous prime is 21006438539. The next prime is 21006438577. The reversal of 21006438574 is 47583460012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006438577) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 569769 + ... + 605515.

It is an arithmetic number, because the mean of its divisors is an integer number (2148526296).

Almost surely, 2^21006438574 is an apocalyptic number.

21006438574 is a deficient number, since it is larger than the sum of its proper divisors (13369982162).

21006438574 is a wasteful number, since it uses less digits than its factorization.

21006438574 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62471.

The product of its (nonzero) digits is 161280, while the sum is 40.

Adding to 21006438574 its reverse (47583460012), we get a palindrome (68589898586).

The spelling of 21006438574 in words is "twenty-one billion, six million, four hundred thirty-eight thousand, five hundred seventy-four".