20011221136 has 20 divisors (see below), whose sum is σ = 38794064764. Its totient is φ = 9999849600.

The previous prime is 20011221127. The next prime is 20011221137. The reversal of 20011221136 is 63112211002.

It can be written as a sum of positive squares in 2 ways, for example, as 8787937536 + 11223283600 = 93744^2 + 105940^2 .

It is not an unprimeable number, because it can be changed into a prime (20011221137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331335 + ... + 387046.

Almost surely, 2^20011221136 is an apocalyptic number.

It is an amenable number.

20011221136 is a deficient number, since it is larger than the sum of its proper divisors (18782843628).

20011221136 is a wasteful number, since it uses less digits than its factorization.

20011221136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 720130 (or 720124 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 20011221136 its reverse (63112211002), we get a palindrome (83123432138).

The spelling of 20011221136 in words is "twenty billion, eleven million, two hundred twenty-one thousand, one hundred thirty-six".