21266124218320 has 80 divisors (see below), whose sum is σ = 49493695482000. Its totient is φ = 8497858166784.

The previous prime is 21266124218267. The next prime is 21266124218321. The reversal of 21266124218320 is 2381242166212.

It can be written as a sum of positive squares in 8 ways, for example, as 4722641770896 + 16543482447424 = 2173164^2 + 4067368^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21266124218321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 487632676 + ... + 487676284.

It is an arithmetic number, because the mean of its divisors is an integer number (618671193525).

Almost surely, 2^{21266124218320} is an apocalyptic number.

21266124218320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21266124218320 is an abundant number, since it is smaller than the sum of its proper divisors (28227571263680).

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

21266124218320 is a wasteful number, since it uses less digits than its factorization.

21266124218320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49640 (or 49634 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 40.

The spelling of 21266124218320 in words is "twenty-one trillion, two hundred sixty-six billion, one hundred twenty-four million, two hundred eighteen thousand, three hundred twenty".