20887268640 has 384 divisors, whose sum is σ = 77260055040. Its totient is φ = 4644864000.

The previous prime is 20887268609. The next prime is 20887268641. The reversal of 20887268640 is 4686278802.

It is not an unprimeable number, because it can be changed into a prime (20887268641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 20700456 + ... + 20701464.

It is an arithmetic number, because the mean of its divisors is an integer number (201198060).

Almost surely, 2^20887268640 is an apocalyptic number.

20887268640 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 20887268640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38630027520).

20887268640 is an abundant number, since it is smaller than the sum of its proper divisors (56372786400).

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

20887268640 is a wasteful number, since it uses less digits than its factorization.

20887268640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1196 (or 1188 counting only the distinct ones).

The product of its (nonzero) digits is 2064384, while the sum is 51.

The spelling of 20887268640 in words is "twenty billion, eight hundred eighty-seven million, two hundred sixty-eight thousand, six hundred forty".