20330640 has 240 divisors, whose sum is σ = 79387776. Its totient is φ = 4608000.

The previous prime is 20330591. The next prime is 20330647. The reversal of 20330640 is 4603302.

20330640 is a `hidden beast` number, since 20 + 3 + 3 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

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

It is not an unprimeable number, because it can be changed into a prime (20330647) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 134565 + ... + 134715.

Almost surely, 2^20330640 is an apocalyptic number.

20330640 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 20330640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39693888).

20330640 is an abundant number, since it is smaller than the sum of its proper divisors (59057136).

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

20330640 is a wasteful number, since it uses less digits than its factorization.

20330640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 18.

The square root of 20330640 is about 4508.9510975392. The cubic root of 20330640 is about 272.9294186170.

Adding to 20330640 its reverse (4603302), we get a palindrome (24933942).

The spelling of 20330640 in words is "twenty million, three hundred thirty thousand, six hundred forty".