21266880804 has 168 divisors, whose sum is σ = 63257243840. Its totient is φ = 6199042752.

The previous prime is 21266880797. The next prime is 21266880809. The reversal of 21266880804 is 40808866212.

It is a self number, because there is not a number n which added to its sum of digits gives 21266880804.

It is not an unprimeable number, because it can be changed into a prime (21266880809) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 705489 + ... + 735015.

Almost surely, 2^21266880804 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 21266880804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31628621920).

21266880804 is an abundant number, since it is smaller than the sum of its proper divisors (41990363036).

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

21266880804 is a wasteful number, since it uses less digits than its factorization.

21266880804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29581 (or 29564 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 45.

The spelling of 21266880804 in words is "twenty-one billion, two hundred sixty-six million, eight hundred eighty thousand, eight hundred four".