20005331640 has 128 divisors (see below), whose sum is σ = 69044382720. Its totient is φ = 4542336000.

The previous prime is 20005331639. The next prime is 20005331641. The reversal of 20005331640 is 4613350002.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20005331639) and next prime (20005331641).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20005331640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20005331641) 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, 47980 + ... + 205700.

It is an arithmetic number, because the mean of its divisors is an integer number (539409240).

Almost surely, 2^20005331640 is an apocalyptic number.

20005331640 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 20005331640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34522191360).

20005331640 is an abundant number, since it is smaller than the sum of its proper divisors (49039051080).

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

20005331640 is a wasteful number, since it uses less digits than its factorization.

20005331640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157893 (or 157889 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

Adding to 20005331640 its reverse (4613350002), we get a palindrome (24618681642).

The spelling of 20005331640 in words is "twenty billion, five million, three hundred thirty-one thousand, six hundred forty".