21261024143544 has 128 divisors (see below), whose sum is σ = 57386530080000. Its totient is φ = 6539490207744.

The previous prime is 21261024143543. The next prime is 21261024143563. The reversal of 21261024143544 is 44534142016212.

It is a super-2 number, since 2×21261024143544² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21261024143543) 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 31 ways as a sum of consecutive naturals, for example, 7794907 + ... + 10162805.

It is an arithmetic number, because the mean of its divisors is an integer number (448332266250).

Almost surely, 2^{21261024143544} is an apocalyptic number.

21261024143544 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 21261024143544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28693265040000).

21261024143544 is an abundant number, since it is smaller than the sum of its proper divisors (36125505936456).

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

21261024143544 is a wasteful number, since it uses less digits than its factorization.

21261024143544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2368357 (or 2368353 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 39.

Adding to 21261024143544 its reverse (44534142016212), we get a palindrome (65795166159756).

The spelling of 21261024143544 in words is "twenty-one trillion, two hundred sixty-one billion, twenty-four million, one hundred forty-three thousand, five hundred forty-four".