21606565997594 has 32 divisors (see below), whose sum is σ = 33045872408640. Its totient is φ = 10593788583168.

The previous prime is 21606565997579. The next prime is 21606565997603. The reversal of 21606565997594 is 49579956560612.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8946704 + ... + 11102100.

It is an arithmetic number, because the mean of its divisors is an integer number (1032683512770).

Almost surely, 2^{21606565997594} is an apocalyptic number.

21606565997594 is a deficient number, since it is larger than the sum of its proper divisors (11439306411046).

21606565997594 is a wasteful number, since it uses less digits than its factorization.

21606565997594 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2155982.

The product of its (nonzero) digits is 1102248000, while the sum is 74.

The spelling of 21606565997594 in words is "twenty-one trillion, six hundred six billion, five hundred sixty-five million, nine hundred ninety-seven thousand, five hundred ninety-four".