21105733440 has 224 divisors, whose sum is σ = 73211838336. Its totient is φ = 5108899840.

The previous prime is 21105733433. The next prime is 21105733447. The reversal of 21105733440 is 4433750112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21105733433) and next prime (21105733447).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21105733398 and 21105733407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105733447) 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, 10696294 + ... + 10698266.

It is an arithmetic number, because the mean of its divisors is an integer number (326838564).

Almost surely, 2^21105733440 is an apocalyptic number.

21105733440 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 21105733440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36605919168).

21105733440 is an abundant number, since it is smaller than the sum of its proper divisors (52106104896).

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

21105733440 is a wasteful number, since it uses less digits than its factorization.

21105733440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3017 (or 3007 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 30.

The spelling of 21105733440 in words is "twenty-one billion, one hundred five million, seven hundred thirty-three thousand, four hundred forty".