21261232153504 has 96 divisors (see below), whose sum is σ = 50760225210240. Its totient is φ = 8557594533888.

The previous prime is 21261232153387. The next prime is 21261232153507. The reversal of 21261232153504 is 40535123216212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21261232153507) by changing a digit.

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, 4199509 + ... + 7756180.

It is an arithmetic number, because the mean of its divisors is an integer number (528752345940).

Almost surely, 2^{21261232153504} is an apocalyptic number.

It is an amenable number.

21261232153504 is an abundant number, since it is smaller than the sum of its proper divisors (29498993056736).

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

21261232153504 is a wasteful number, since it uses less digits than its factorization.

21261232153504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11956190 (or 11956182 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 37.

Adding to 21261232153504 its reverse (40535123216212), we get a palindrome (61796355369716).

The spelling of 21261232153504 in words is "twenty-one trillion, two hundred sixty-one billion, two hundred thirty-two million, one hundred fifty-three thousand, five hundred four".