21505041104 has 10 divisors (see below), whose sum is σ = 41666017170. Its totient is φ = 10752520544.

The previous prime is 21505041083. The next prime is 21505041109. The reversal of 21505041104 is 40114050512.

It can be written as a sum of positive squares in only one way, i.e., 18441640000 + 3063401104 = 135800^2 + 55348^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21505041104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21505041109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 672032519 + ... + 672032550.

It is an arithmetic number, because the mean of its divisors is an integer number (4166601717).

Almost surely, 2^21505041104 is an apocalyptic number.

It is an amenable number.

21505041104 is a deficient number, since it is larger than the sum of its proper divisors (20160976066).

21505041104 is a wasteful number, since it uses less digits than its factorization.

21505041104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1344065077 (or 1344065071 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 23.

Adding to 21505041104 its reverse (40114050512), we get a palindrome (61619091616).

The spelling of 21505041104 in words is "twenty-one billion, five hundred five million, forty-one thousand, one hundred four".