21554120144 has 60 divisors (see below), whose sum is σ = 45100256256. Its totient is φ = 9972293184.

The previous prime is 21554120143. The next prime is 21554120171. The reversal of 21554120144 is 44102145512.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554120143) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 204977 + ... + 291759.

Almost surely, 2^21554120144 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 21554120144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22550128128).

21554120144 is an abundant number, since it is smaller than the sum of its proper divisors (23546136112).

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

21554120144 is a wasteful number, since it uses less digits than its factorization.

21554120144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86872 (or 86847 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 29.

Adding to 21554120144 its reverse (44102145512), we get a palindrome (65656265656).

The spelling of 21554120144 in words is "twenty-one billion, five hundred fifty-four million, one hundred twenty thousand, one hundred forty-four".