20505591936 has 176 divisors, whose sum is σ = 61298716110. Its totient is φ = 6832677888.

The previous prime is 20505591907. The next prime is 20505591941. The reversal of 20505591936 is 63919550502.

20505591936 is a `hidden beast` number, since 2 + 0 + 5 + 0 + 559 + 1 + 93 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11431886400 + 9073705536 = 106920^2 + 95256^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20505591891 and 20505591900.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 21 ways as a sum of consecutive naturals, for example, 7556916 + ... + 7559628.

Almost surely, 2^20505591936 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 20505591936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30649358055).

20505591936 is an abundant number, since it is smaller than the sum of its proper divisors (40793124174).

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

20505591936 is an frugal number, since it uses more digits than its factorization.

20505591936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2757 (or 2718 counting only the distinct ones).

The product of its (nonzero) digits is 364500, while the sum is 45.

The spelling of 20505591936 in words is "twenty billion, five hundred five million, five hundred ninety-one thousand, nine hundred thirty-six".