20156220016409 has 4 divisors (see below), whose sum is σ = 20156284212660. Its totient is φ = 20156155820160.

The previous prime is 20156220016403. The next prime is 20156220016417. The reversal of 20156220016409 is 90461002265102.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 124750240000 + 20031469776409 = 353200^2 + 4475653^2 .

It is a cyclic number.

It is not a de Polignac number, because 20156220016409 - 2⁴⁰ = 19056708388633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20156220016403) 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, 31624832 + ... + 32255889.

It is an arithmetic number, because the mean of its divisors is an integer number (5039071053165).

Almost surely, 2^{20156220016409} is an apocalyptic number.

It is an amenable number.

20156220016409 is a deficient number, since it is larger than the sum of its proper divisors (64196251).

20156220016409 is an equidigital number, since it uses as much as digits as its factorization.

20156220016409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64196250.

The product of its (nonzero) digits is 51840, while the sum is 38.

The spelling of 20156220016409 in words is "twenty trillion, one hundred fifty-six billion, two hundred twenty million, sixteen thousand, four hundred nine".