21155031244424 has 32 divisors (see below), whose sum is σ = 49453319793600. Its totient is φ = 8242219965120.

The previous prime is 21155031244379. The next prime is 21155031244429. The reversal of 21155031244424 is 42444213055112.

It is not an unprimeable number, because it can be changed into a prime (21155031244429) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 17171290979 + ... + 17171292210.

It is an arithmetic number, because the mean of its divisors is an integer number (1545416243550).

Almost surely, 2^{21155031244424} is an apocalyptic number.

It is an amenable number.

21155031244424 is an abundant number, since it is smaller than the sum of its proper divisors (28298288549176).

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

21155031244424 is a wasteful number, since it uses less digits than its factorization.

21155031244424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34342583213 (or 34342583209 counting only the distinct ones).

The product of its (nonzero) digits is 153600, while the sum is 38.

Adding to 21155031244424 its reverse (42444213055112), we get a palindrome (63599244299536).

The spelling of 21155031244424 in words is "twenty-one trillion, one hundred fifty-five billion, thirty-one million, two hundred forty-four thousand, four hundred twenty-four".