21708799558 has 4 divisors (see below), whose sum is σ = 32563199340. Its totient is φ = 10854399778.

The previous prime is 21708799513. The next prime is 21708799559. The reversal of 21708799558 is 85599780712.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 21708799496 and 21708799505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21708799559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5427199888 + ... + 5427199891.

It is an arithmetic number, because the mean of its divisors is an integer number (8140799835).

Almost surely, 2^21708799558 is an apocalyptic number.

21708799558 is a deficient number, since it is larger than the sum of its proper divisors (10854399782).

21708799558 is a wasteful number, since it uses less digits than its factorization.

21708799558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10854399781.

The product of its (nonzero) digits is 12700800, while the sum is 61.

The spelling of 21708799558 in words is "twenty-one billion, seven hundred eight million, seven hundred ninety-nine thousand, five hundred fifty-eight".