21066888240 has 600 divisors, whose sum is σ = 80454448800. Its totient is φ = 5091102720.

The previous prime is 21066888187. The next prime is 21066888247. The reversal of 21066888240 is 4288866012.

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

It is not an unprimeable number, because it can be changed into a prime (21066888247) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 105863661 + ... + 105863859.

It is an arithmetic number, because the mean of its divisors is an integer number (134090748).

Almost surely, 2^21066888240 is an apocalyptic number.

21066888240 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 21066888240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40227224400).

21066888240 is an abundant number, since it is smaller than the sum of its proper divisors (59387560560).

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

21066888240 is a wasteful number, since it uses less digits than its factorization.

21066888240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303 (or 257 counting only the distinct ones).

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

The spelling of 21066888240 in words is "twenty-one billion, sixty-six million, eight hundred eighty-eight thousand, two hundred forty".