21246782920 has 96 divisors (see below), whose sum is σ = 55399697280. Its totient is φ = 7271582720.

The previous prime is 21246782863. The next prime is 21246782929. The reversal of 21246782920 is 2928764212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21246782929) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43617 + ... + 210703.

It is an arithmetic number, because the mean of its divisors is an integer number (577080180).

Almost surely, 2^21246782920 is an apocalyptic number.

21246782920 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 21246782920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27699848640).

21246782920 is an abundant number, since it is smaller than the sum of its proper divisors (34152914360).

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

21246782920 is a wasteful number, since it uses less digits than its factorization.

21246782920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167143 (or 167122 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 43.

The spelling of 21246782920 in words is "twenty-one billion, two hundred forty-six million, seven hundred eighty-two thousand, nine hundred twenty".