20617872804 has 72 divisors (see below), whose sum is σ = 53453155392. Its totient is φ = 6698203200.

The previous prime is 20617872797. The next prime is 20617872809. The reversal of 20617872804 is 40827871602.

20617872804 is a `hidden beast` number, since 2 + 0 + 617 + 8 + 7 + 28 + 0 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 20617872804.

It is not an unprimeable number, because it can be changed into a prime (20617872809) 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, 252327 + ... + 323889.

It is an arithmetic number, because the mean of its divisors is an integer number (742404936).

Almost surely, 2^20617872804 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20617872804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26726577696).

20617872804 is an abundant number, since it is smaller than the sum of its proper divisors (32835282588).

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

20617872804 is a wasteful number, since it uses less digits than its factorization.

20617872804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71777 (or 71772 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The spelling of 20617872804 in words is "twenty billion, six hundred seventeen million, eight hundred seventy-two thousand, eight hundred four".