21423750287856 has 320 divisors, whose sum is σ = 71120455142400. Its totient is φ = 5409495318528.

The previous prime is 21423750287851. The next prime is 21423750287921. The reversal of 21423750287856 is 65878205732412.

It is a super-2 number, since 2×21423750287856² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21423750287856.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21423750287851) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11390200 + ... + 13137128.

It is an arithmetic number, because the mean of its divisors is an integer number (222251422320).

Almost surely, 2^{21423750287856} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21423750287856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35560227571200).

21423750287856 is an abundant number, since it is smaller than the sum of its proper divisors (49696704854544).

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

21423750287856 is a wasteful number, since it uses less digits than its factorization.

21423750287856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1747096 (or 1747090 counting only the distinct ones).

The product of its (nonzero) digits is 45158400, while the sum is 60.

The spelling of 21423750287856 in words is "twenty-one trillion, four hundred twenty-three billion, seven hundred fifty million, two hundred eighty-seven thousand, eight hundred fifty-six".