20923517440 has 240 divisors, whose sum is σ = 61436469600. Its totient is φ = 6795436032.

The previous prime is 20923517437. The next prime is 20923517443. The reversal of 20923517440 is 4471532902.

It is an interprime number because it is at equal distance from previous prime (20923517437) and next prime (20923517443).

It is a self number, because there is not a number n which added to its sum of digits gives 20923517440.

It is not an unprimeable number, because it can be changed into a prime (20923517443) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2378971 + ... + 2387749.

It is an arithmetic number, because the mean of its divisors is an integer number (255985290).

Almost surely, 2^20923517440 is an apocalyptic number.

20923517440 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 20923517440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30718234800).

20923517440 is an abundant number, since it is smaller than the sum of its proper divisors (40512952160).

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

20923517440 is an equidigital number, since it uses as much as digits as its factorization.

20923517440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8835 (or 8812 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 37.

The spelling of 20923517440 in words is "twenty billion, nine hundred twenty-three million, five hundred seventeen thousand, four hundred forty".