20121020136 has 144 divisors (see below), whose sum is σ = 65739623040. Its totient is φ = 5748835680.

The previous prime is 20121020069. The next prime is 20121020147. The reversal of 20121020136 is 63102012102.

It is a Harshad number since it is a multiple of its sum of digits (18).

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 35 ways as a sum of consecutive naturals, for example, 10360 + ... + 200871.

It is an arithmetic number, because the mean of its divisors is an integer number (456525160).

Almost surely, 2^20121020136 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 20121020136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32869811520).

20121020136 is an abundant number, since it is smaller than the sum of its proper divisors (45618602904).

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

20121020136 is a wasteful number, since it uses less digits than its factorization.

20121020136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211266 (or 211243 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 20121020136 its reverse (63102012102), we get a palindrome (83223032238).

The spelling of 20121020136 in words is "twenty billion, one hundred twenty-one million, twenty thousand, one hundred thirty-six".