21810505017 has 16 divisors (see below), whose sum is σ = 34045667712. Its totient is φ = 12159166080.

The previous prime is 21810505009. The next prime is 21810505037. The reversal of 21810505017 is 71050501812.

It is not a de Polignac number, because 21810505017 - 2³ = 21810505009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21810505037) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12664938 + ... + 12666659.

It is an arithmetic number, because the mean of its divisors is an integer number (2127854232).

Almost surely, 2^21810505017 is an apocalyptic number.

It is an amenable number.

21810505017 is a deficient number, since it is larger than the sum of its proper divisors (12235162695).

21810505017 is a wasteful number, since it uses less digits than its factorization.

21810505017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25331648.

The product of its (nonzero) digits is 2800, while the sum is 30.

The spelling of 21810505017 in words is "twenty-one billion, eight hundred ten million, five hundred five thousand, seventeen".