20011200021 has 24 divisors (see below), whose sum is σ = 30610718424. Its totient is φ = 12553850880.

The previous prime is 20011199981. The next prime is 20011200031. The reversal of 20011200021 is 12000211002.

It can be written as a sum of positive squares in 4 ways, for example, as 3051347121 + 16959852900 = 55239^2 + 130230^2 .

It is not a de Polignac number, because 20011200021 - 2¹⁹ = 20010675733 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 20011199976 and 20011200012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011200031) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1707301 + ... + 1718981.

It is an arithmetic number, because the mean of its divisors is an integer number (1275446601).

Almost surely, 2^20011200021 is an apocalyptic number.

It is an amenable number.

20011200021 is a deficient number, since it is larger than the sum of its proper divisors (10599518403).

20011200021 is a wasteful number, since it uses less digits than its factorization.

20011200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22901 (or 22898 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 20011200021 its reverse (12000211002), we get a palindrome (32011411023).

The spelling of 20011200021 in words is "twenty billion, eleven million, two hundred thousand, twenty-one".