21126042756 has 192 divisors, whose sum is σ = 67633359360. Its totient is φ = 5553308160.

The previous prime is 21126042713. The next prime is 21126042767. The reversal of 21126042756 is 65724062112.

It is a happy number.

21126042756 is a `hidden beast` number, since 21 + 1 + 2 + 604 + 27 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21126042756.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 3112086 + ... + 3118866.

It is an arithmetic number, because the mean of its divisors is an integer number (352257080).

Almost surely, 2^21126042756 is an apocalyptic number.

21126042756 is a gapful number since it is divisible by the number (26) 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 21126042756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33816679680).

21126042756 is an abundant number, since it is smaller than the sum of its proper divisors (46507316604).

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

21126042756 is a wasteful number, since it uses less digits than its factorization.

21126042756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7131 (or 7123 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

It can be divided in two parts, 211260 and 42756, that added together give a square (254016 = 504²).

The spelling of 21126042756 in words is "twenty-one billion, one hundred twenty-six million, forty-two thousand, seven hundred fifty-six".