20503172640 has 96 divisors (see below), whose sum is σ = 64630621440. Its totient is φ = 5463650304.

The previous prime is 20503172639. The next prime is 20503172671. The reversal of 20503172640 is 4627130502.

It is a tau number, because it is divible by the number of its divisors (96).

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 = 20503172598 and 20503172607.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 700377 + ... + 729063.

It is an arithmetic number, because the mean of its divisors is an integer number (673235640).

Almost surely, 2^20503172640 is an apocalyptic number.

20503172640 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 20503172640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32315310720).

20503172640 is an abundant number, since it is smaller than the sum of its proper divisors (44127448800).

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

20503172640 is a wasteful number, since it uses less digits than its factorization.

20503172640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30194 (or 30186 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 30.

The spelling of 20503172640 in words is "twenty billion, five hundred three million, one hundred seventy-two thousand, six hundred forty".