21008215005 has 32 divisors (see below), whose sum is σ = 34766807040. Its totient is φ = 10821272640.

The previous prime is 21008214979. The next prime is 21008215027. The reversal of 21008215005 is 50051280012.

It is not a de Polignac number, because 21008215005 - 2¹⁴ = 21008198621 is a prime.

It is a Curzon number.

It is a congruent number.

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, 188986 + ... + 278804.

It is an arithmetic number, because the mean of its divisors is an integer number (1086462720).

Almost surely, 2^21008215005 is an apocalyptic number.

It is an amenable number.

21008215005 is a deficient number, since it is larger than the sum of its proper divisors (13758592035).

21008215005 is a wasteful number, since it uses less digits than its factorization.

21008215005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90361.

The product of its (nonzero) digits is 800, while the sum is 24.

Adding to 21008215005 its reverse (50051280012), we get a palindrome (71059495017).

The spelling of 21008215005 in words is "twenty-one billion, eight million, two hundred fifteen thousand, five".