21266721521280 has 512 divisors, whose sum is σ = 77830325452800. Its totient is φ = 5482467348480.

The previous prime is 21266721521239. The next prime is 21266721521293. The reversal of 21266721521280 is 8212512766212.

21266721521280 is a `hidden beast` number, since 2 + 1 + 26 + 6 + 7 + 21 + 521 + 2 + 80 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 526553247 + ... + 526593633.

It is an arithmetic number, because the mean of its divisors is an integer number (152012354400).

Almost surely, 2^{21266721521280} is an apocalyptic number.

21266721521280 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 21266721521280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38915162726400).

21266721521280 is an abundant number, since it is smaller than the sum of its proper divisors (56563603931520).

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

21266721521280 is a wasteful number, since it uses less digits than its factorization.

21266721521280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41429 (or 41411 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 21266721521280 in words is "twenty-one trillion, two hundred sixty-six billion, seven hundred twenty-one million, five hundred twenty-one thousand, two hundred eighty".