21155004024 has 144 divisors (see below), whose sum is σ = 67624036200. Its totient is φ = 5494769280.

The previous prime is 21155004011. The next prime is 21155004041. The reversal of 21155004024 is 42040055112.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 21155003985 and 21155004003.

It is a congruent 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 35 ways as a sum of consecutive naturals, for example, 67962 + ... + 216630.

Almost surely, 2^21155004024 is an apocalyptic number.

21155004024 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21155004024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33812018100).

21155004024 is an abundant number, since it is smaller than the sum of its proper divisors (46469032176).

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

21155004024 is a wasteful number, since it uses less digits than its factorization.

21155004024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148714 (or 148692 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 24.

Adding to 21155004024 its reverse (42040055112), we get a palindrome (63195059136).

The spelling of 21155004024 in words is "twenty-one billion, one hundred fifty-five million, four thousand, twenty-four".