21009400215 has 16 divisors (see below), whose sum is σ = 33619468128. Its totient is φ = 11203537536.

The previous prime is 21009400201. The next prime is 21009400267. The reversal of 21009400215 is 51200490012.

It is not a de Polignac number, because 21009400215 - 2²⁸ = 20740964759 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30717 + ... + 207273.

It is an arithmetic number, because the mean of its divisors is an integer number (2101216758).

Almost surely, 2^21009400215 is an apocalyptic number.

21009400215 is a deficient number, since it is larger than the sum of its proper divisors (12610067913).

21009400215 is a wasteful number, since it uses less digits than its factorization.

21009400215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184498.

The product of its (nonzero) digits is 720, while the sum is 24.

Adding to 21009400215 its reverse (51200490012), we get a palindrome (72209890227).

The spelling of 21009400215 in words is "twenty-one billion, nine million, four hundred thousand, two hundred fifteen".