21709208842 has 8 divisors (see below), whose sum is σ = 33178224996. Its totient is φ = 10649800512.

The previous prime is 21709208837. The next prime is 21709208863. The reversal of 21709208842 is 24880290712.

It can be written as a sum of positive squares in 2 ways, for example, as 19148747641 + 2560461201 = 138379^2 + 50601^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 102401823 + ... + 102402034.

Almost surely, 2^21709208842 is an apocalyptic number.

21709208842 is a deficient number, since it is larger than the sum of its proper divisors (11469016154).

21709208842 is a wasteful number, since it uses less digits than its factorization.

21709208842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204803912.

The product of its (nonzero) digits is 129024, while the sum is 43.

The spelling of 21709208842 in words is "twenty-one billion, seven hundred nine million, two hundred eight thousand, eight hundred forty-two".