21183317428 has 96 divisors (see below), whose sum is σ = 46216235520. Its totient is φ = 8272281600.

The previous prime is 21183317401. The next prime is 21183317447. The reversal of 21183317428 is 82471338112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15033588 + ... + 15034996.

It is an arithmetic number, because the mean of its divisors is an integer number (481419120).

Almost surely, 2^21183317428 is an apocalyptic number.

21183317428 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 21183317428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23108117760).

21183317428 is an abundant number, since it is smaller than the sum of its proper divisors (25032918092).

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

21183317428 is a wasteful number, since it uses less digits than its factorization.

21183317428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1937 (or 1935 counting only the distinct ones).

The product of its digits is 64512, while the sum is 40.

The spelling of 21183317428 in words is "twenty-one billion, one hundred eighty-three million, three hundred seventeen thousand, four hundred twenty-eight".