21705299216 has 20 divisors (see below), whose sum is σ = 42136653900. Its totient is φ = 10831324032.

The previous prime is 21705299149. The next prime is 21705299267. The reversal of 21705299216 is 61299250712.

It can be written as a sum of positive squares in 2 ways, for example, as 7587106816 + 14118192400 = 87104^2 + 118820^2 .

It is a super-2 number, since 2×21705299216² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1324451 + ... + 1340738.

It is an arithmetic number, because the mean of its divisors is an integer number (2106832695).

Almost surely, 2^21705299216 is an apocalyptic number.

It is an amenable number.

21705299216 is a deficient number, since it is larger than the sum of its proper divisors (20431354684).

21705299216 is a wasteful number, since it uses less digits than its factorization.

21705299216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2665706 (or 2665700 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 44.

The spelling of 21705299216 in words is "twenty-one billion, seven hundred five million, two hundred ninety-nine thousand, two hundred sixteen".