21287174748 has 96 divisors (see below), whose sum is σ = 57791838720. Its totient is φ = 5972348160.

The previous prime is 21287174743. The next prime is 21287174749. The reversal of 21287174748 is 84747178212.

It is a self number, because there is not a number n which added to its sum of digits gives 21287174748.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21287174743) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6009858 + ... + 6013398.

It is an arithmetic number, because the mean of its divisors is an integer number (601998320).

Almost surely, 2^21287174748 is an apocalyptic number.

21287174748 is a gapful number since it is divisible by the number (28) 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 21287174748, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28895919360).

21287174748 is an abundant number, since it is smaller than the sum of its proper divisors (36504663972).

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

21287174748 is a wasteful number, since it uses less digits than its factorization.

21287174748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4827 (or 4825 counting only the distinct ones).

The product of its digits is 1404928, while the sum is 51.

The spelling of 21287174748 in words is "twenty-one billion, two hundred eighty-seven million, one hundred seventy-four thousand, seven hundred forty-eight".