20311200640 has 128 divisors (see below), whose sum is σ = 53335065600. Its totient is φ = 7362127872.

The previous prime is 20311200601. The next prime is 20311200647. The reversal of 20311200640 is 4600211302.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20311200647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 243369 + ... + 315991.

It is an arithmetic number, because the mean of its divisors is an integer number (416680200).

Almost surely, 2^20311200640 is an apocalyptic number.

20311200640 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 20311200640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26667532800).

20311200640 is an abundant number, since it is smaller than the sum of its proper divisors (33023864960).

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

20311200640 is a wasteful number, since it uses less digits than its factorization.

20311200640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72684 (or 72672 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 20311200640 its reverse (4600211302), we get a palindrome (24911411942).

The spelling of 20311200640 in words is "twenty billion, three hundred eleven million, two hundred thousand, six hundred forty".