21606708018 has 32 divisors (see below), whose sum is σ = 49672250496. Its totient is φ = 6137659008.

The previous prime is 21606708017. The next prime is 21606708023. The reversal of 21606708018 is 81080760612.

It is not an unprimeable number, because it can be changed into a prime (21606708017) by changing a digit.

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, 1479571 + ... + 1494102.

It is an arithmetic number, because the mean of its divisors is an integer number (1552257828).

Almost surely, 2^21606708018 is an apocalyptic number.

21606708018 is an abundant number, since it is smaller than the sum of its proper divisors (28065542478).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21606708018 is a wasteful number, since it uses less digits than its factorization.

21606708018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2973858.

The product of its (nonzero) digits is 32256, while the sum is 39.

The spelling of 21606708018 in words is "twenty-one billion, six hundred six million, seven hundred eight thousand, eighteen".