20311715640 has 128 divisors (see below), whose sum is σ = 63207555840. Its totient is φ = 5217924096.

The previous prime is 20311715639. The next prime is 20311715647. The reversal of 20311715640 is 4651711302.

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 = 20311715598 and 20311715607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20311715647) 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, 349719 + ... + 403641.

It is an arithmetic number, because the mean of its divisors is an integer number (493809030).

Almost surely, 2^20311715640 is an apocalyptic number.

20311715640 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 20311715640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31603777920).

20311715640 is an abundant number, since it is smaller than the sum of its proper divisors (42895840200).

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

20311715640 is a wasteful number, since it uses less digits than its factorization.

20311715640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54053 (or 54049 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 30.

The spelling of 20311715640 in words is "twenty billion, three hundred eleven million, seven hundred fifteen thousand, six hundred forty".