20001251536 has 160 divisors (see below), whose sum is σ = 49090572288. Its totient is φ = 7692072960.

The previous prime is 20001251489. The next prime is 20001251539. The reversal of 20001251536 is 63515210002.

It is a self number, because there is not a number n which added to its sum of digits gives 20001251536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001251539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19399341 + ... + 19400371.

Almost surely, 2^20001251536 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 20001251536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24545286144).

20001251536 is an abundant number, since it is smaller than the sum of its proper divisors (29089320752).

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

20001251536 is a wasteful number, since it uses less digits than its factorization.

20001251536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1529 (or 1523 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 20001251536 its reverse (63515210002), we get a palindrome (83516461538).

The spelling of 20001251536 in words is "twenty billion, one million, two hundred fifty-one thousand, five hundred thirty-six".