20638364560 has 160 divisors (see below), whose sum is σ = 52916613120. Its totient is φ = 7423680000.

The previous prime is 20638364557. The next prime is 20638364563. The reversal of 20638364560 is 6546383602.

It is an interprime number because it is at equal distance from previous prime (20638364557) and next prime (20638364563).

It is a super-2 number, since 2×20638364560² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20638364563) 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, 49256031 + ... + 49256449.

It is an arithmetic number, because the mean of its divisors is an integer number (330728832).

Almost surely, 2^20638364560 is an apocalyptic number.

20638364560 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 20638364560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26458306560).

20638364560 is an abundant number, since it is smaller than the sum of its proper divisors (32278248560).

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

20638364560 is a wasteful number, since it uses less digits than its factorization.

20638364560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 917 (or 911 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 43.

The spelling of 20638364560 in words is "twenty billion, six hundred thirty-eight million, three hundred sixty-four thousand, five hundred sixty".