21706116215 has 16 divisors (see below), whose sum is σ = 29835606528. Its totient is φ = 14850584736.

The previous prime is 21706116199. The next prime is 21706116233. The reversal of 21706116215 is 51261160712.

It is a cyclic number.

It is not a de Polignac number, because 21706116215 - 2⁴ = 21706116199 is a prime.

It is a super-2 number, since 2×21706116215² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 684467 + ... + 715476.

It is an arithmetic number, because the mean of its divisors is an integer number (1864725408).

Almost surely, 2^21706116215 is an apocalyptic number.

21706116215 is a deficient number, since it is larger than the sum of its proper divisors (8129490313).

21706116215 is a wasteful number, since it uses less digits than its factorization.

21706116215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1400398.

The product of its (nonzero) digits is 5040, while the sum is 32.

Adding to 21706116215 its reverse (51261160712), we get a palindrome (72967276927).

The spelling of 21706116215 in words is "twenty-one billion, seven hundred six million, one hundred sixteen thousand, two hundred fifteen".