20915351387136 has 440 divisors, whose sum is σ = 65837186096000. Its totient is φ = 6595542982656.

The previous prime is 20915351387129. The next prime is 20915351387141. The reversal of 20915351387136 is 63178315351902.

20915351387136 is a `hidden beast` number, since 2 + 0 + 9 + 1 + 53 + 513 + 8 + 71 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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 39 ways as a sum of consecutive naturals, for example, 1164607725 + ... + 1164625683.

It is an arithmetic number, because the mean of its divisors is an integer number (149629968400).

Almost surely, 2^{20915351387136} 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 20915351387136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32918593048000).

20915351387136 is an abundant number, since it is smaller than the sum of its proper divisors (44921834708864).

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

20915351387136 is a wasteful number, since it uses less digits than its factorization.

20915351387136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18749 (or 18722 counting only the distinct ones).

The product of its (nonzero) digits is 4082400, while the sum is 54.

The spelling of 20915351387136 in words is "twenty trillion, nine hundred fifteen billion, three hundred fifty-one million, three hundred eighty-seven thousand, one hundred thirty-six".