20011220129 has 8 divisors (see below), whose sum is σ = 20341960680. Its totient is φ = 19680566400.

The previous prime is 20011220113. The next prime is 20011220153. The reversal of 20011220129 is 92102211002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2318229904 + 17692990225 = 48148^2 + 133015^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20011220129 - 2⁴ = 20011220113 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20011220129.

It is not an unprimeable number, because it can be changed into a prime (20011220179) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 579119 + ... + 612699.

It is an arithmetic number, because the mean of its divisors is an integer number (2542745085).

Almost surely, 2^20011220129 is an apocalyptic number.

It is an amenable number.

20011220129 is a deficient number, since it is larger than the sum of its proper divisors (330740551).

20011220129 is an equidigital number, since it uses as much as digits as its factorization.

20011220129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43411.

The product of its (nonzero) digits is 144, while the sum is 20.

The spelling of 20011220129 in words is "twenty billion, eleven million, two hundred twenty thousand, one hundred twenty-nine".