20724785136 has 720 divisors, whose sum is σ = 72736844544. Its totient is φ = 5474304000.

The previous prime is 20724785129. The next prime is 20724785161. The reversal of 20724785136 is 63158742702.

20724785136 is a `hidden beast` number, since 20 + 72 + 47 + 8 + 513 + 6 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 20724785091 and 20724785100.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 339750546 + ... + 339750606.

Almost surely, 2^20724785136 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 20724785136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36368422272).

20724785136 is an abundant number, since it is smaller than the sum of its proper divisors (52012059408).

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

20724785136 is a wasteful number, since it uses less digits than its factorization.

20724785136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 45.

The spelling of 20724785136 in words is "twenty billion, seven hundred twenty-four million, seven hundred eighty-five thousand, one hundred thirty-six".