21013016505 has 32 divisors (see below), whose sum is σ = 37185625344. Its totient is φ = 10065275136.

The previous prime is 21013016483. The next prime is 21013016513. The reversal of 21013016505 is 50561031012.

It is not a de Polignac number, because 21013016505 - 2⁵ = 21013016473 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1448989 + ... + 1463418.

It is an arithmetic number, because the mean of its divisors is an integer number (1162050792).

Almost surely, 2^21013016505 is an apocalyptic number.

It is an amenable number.

21013016505 is a deficient number, since it is larger than the sum of its proper divisors (16172608839).

21013016505 is a wasteful number, since it uses less digits than its factorization.

21013016505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2912465.

The product of its (nonzero) digits is 900, while the sum is 24.

Adding to 21013016505 its reverse (50561031012), we get a palindrome (71574047517).

The spelling of 21013016505 in words is "twenty-one billion, thirteen million, sixteen thousand, five hundred five".