21556838417 has 8 divisors (see below), whose sum is σ = 22732903200. Its totient is φ = 20384923104.

The previous prime is 21556838383. The next prime is 21556838431. The reversal of 21556838417 is 71483865512.

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

It is a cyclic number.

It is not a de Polignac number, because 21556838417 - 2²⁴ = 21540061201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21556838477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1026692 + ... + 1047477.

It is an arithmetic number, because the mean of its divisors is an integer number (2841612900).

Almost surely, 2^21556838417 is an apocalyptic number.

It is an amenable number.

21556838417 is a deficient number, since it is larger than the sum of its proper divisors (1176064783).

21556838417 is a wasteful number, since it uses less digits than its factorization.

21556838417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2074735.

The product of its digits is 1612800, while the sum is 50.

The spelling of 21556838417 in words is "twenty-one billion, five hundred fifty-six million, eight hundred thirty-eight thousand, four hundred seventeen".