21133851648 has 352 divisors, whose sum is σ = 73423171584. Its totient is φ = 5244715008.

The previous prime is 21133851647. The next prime is 21133851659. The reversal of 21133851648 is 84615833112.

It is a happy number.

It is a super-3 number, since 3×21133851648³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133851647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4750161 + ... + 4754607.

Almost surely, 2^21133851648 is an apocalyptic number.

21133851648 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 21133851648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36711585792).

21133851648 is an abundant number, since it is smaller than the sum of its proper divisors (52289319936).

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

21133851648 is a wasteful number, since it uses less digits than its factorization.

21133851648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4507 (or 4489 counting only the distinct ones).

The product of its digits is 138240, while the sum is 42.

The spelling of 21133851648 in words is "twenty-one billion, one hundred thirty-three million, eight hundred fifty-one thousand, six hundred forty-eight".