21655560117 has 16 divisors (see below), whose sum is σ = 28926758912. Its totient is φ = 14410727280.

The previous prime is 21655560107. The next prime is 21655560149. The reversal of 21655560117 is 71106555612.

It is a happy number.

It is not a de Polignac number, because 21655560117 - 2⁶ = 21655560053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21655560107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6384492 + ... + 6387882.

It is an arithmetic number, because the mean of its divisors is an integer number (1807922432).

Almost surely, 2^21655560117 is an apocalyptic number.

It is an amenable number.

21655560117 is a deficient number, since it is larger than the sum of its proper divisors (7271198795).

21655560117 is a wasteful number, since it uses less digits than its factorization.

21655560117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6648.

The product of its (nonzero) digits is 63000, while the sum is 39.

It can be divided in two parts, 216555 and 60117, that added together give a palindrome (276672).

The spelling of 21655560117 in words is "twenty-one billion, six hundred fifty-five million, five hundred sixty thousand, one hundred seventeen".