21268487520 has 768 divisors, whose sum is σ = 90855475200. Its totient is φ = 4595429376.

The previous prime is 21268487503. The next prime is 21268487521. The reversal of 21268487520 is 2578486212.

21268487520 is a `hidden beast` number, since 21 + 2 + 68 + 48 + 7 + 520 = 666.

It is a super-2 number, since 2×21268487520² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21268487521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 46539132 + ... + 46539588.

It is an arithmetic number, because the mean of its divisors is an integer number (118301400).

Almost surely, 2^21268487520 is an apocalyptic number.

21268487520 is a gapful number since it is divisible by the number (20) 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 21268487520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45427737600).

21268487520 is an abundant number, since it is smaller than the sum of its proper divisors (69586987680).

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

21268487520 is an equidigital number, since it uses as much as digits as its factorization.

21268487520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519 (or 493 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

The spelling of 21268487520 in words is "twenty-one billion, two hundred sixty-eight million, four hundred eighty-seven thousand, five hundred twenty".