20911632409 has 4 divisors (see below), whose sum is σ = 20912480820. Its totient is φ = 20910784000.

The previous prime is 20911632331. The next prime is 20911632431. The reversal of 20911632409 is 90423611902.

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 844076809 + 20067555600 = 29053^2 + 141660^2 .

It is a cyclic number.

It is not a de Polignac number, because 20911632409 - 2²⁹ = 20374761497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20911632449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 386092 + ... + 436909.

It is an arithmetic number, because the mean of its divisors is an integer number (5228120205).

Almost surely, 2^20911632409 is an apocalyptic number.

It is an amenable number.

20911632409 is a deficient number, since it is larger than the sum of its proper divisors (848411).

20911632409 is an equidigital number, since it uses as much as digits as its factorization.

20911632409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 848410.

The product of its (nonzero) digits is 23328, while the sum is 37.

The spelling of 20911632409 in words is "twenty billion, nine hundred eleven million, six hundred thirty-two thousand, four hundred nine".