20730240 has 192 divisors, whose sum is σ = 73990800. Its totient is φ = 5345280.

The previous prime is 20730239. The next prime is 20730253. The reversal of 20730240 is 4203702.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 339810 + ... + 339870.

Almost surely, 2^20730240 is an apocalyptic number.

20730240 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 20730240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36995400).

20730240 is an abundant number, since it is smaller than the sum of its proper divisors (53260560).

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

20730240 is a wasteful number, since it uses less digits than its factorization.

20730240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 18.

The square root of 20730240 is about 4553.0473311838. The cubic root of 20730240 is about 274.7059777628.

Adding to 20730240 its reverse (4203702), we get a palindrome (24933942).

The spelling of 20730240 in words is "twenty million, seven hundred thirty thousand, two hundred forty".