21655236610144 has 96 divisors (see below), whose sum is σ = 44861494035456. Its totient is φ = 10269925585920.

The previous prime is 21655236610087. The next prime is 21655236610153. The reversal of 21655236610144 is 44101663255612.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a junction number, because it is equal to n+sod(n) for n = 21655236610094 and 21655236610103.

It is a congruent number.

It is an unprimeable number.

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, 91740079 + ... + 91975825.

It is an arithmetic number, because the mean of its divisors is an integer number (467307229536).

Almost surely, 2^{21655236610144} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21655236610144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22430747017728).

21655236610144 is an abundant number, since it is smaller than the sum of its proper divisors (23206257425312).

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

21655236610144 is a wasteful number, since it uses less digits than its factorization.

21655236610144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236828 (or 236820 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 46.

Adding to 21655236610144 its reverse (44101663255612), we get a palindrome (65756899865756).

The spelling of 21655236610144 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred thirty-six million, six hundred ten thousand, one hundred forty-four".