20949035809 has 16 divisors (see below), whose sum is σ = 23178152592. Its totient is φ = 18808512768.

The previous prime is 20949035773. The next prime is 20949035839. The reversal of 20949035809 is 90853094902.

It can be written as a sum of positive squares in 8 ways, for example, as 1160424225 + 19788611584 = 34065^2 + 140672^2 .

It is a cyclic number.

It is not a de Polignac number, because 20949035809 - 2¹¹ = 20949033761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20949035839) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1924827 + ... + 1935679.

It is an arithmetic number, because the mean of its divisors is an integer number (1448634537).

Almost surely, 2^20949035809 is an apocalyptic number.

It is an amenable number.

20949035809 is a deficient number, since it is larger than the sum of its proper divisors (2229116783).

20949035809 is a wasteful number, since it uses less digits than its factorization.

20949035809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14916.

The product of its (nonzero) digits is 699840, while the sum is 49.

The spelling of 20949035809 in words is "twenty billion, nine hundred forty-nine million, thirty-five thousand, eight hundred nine".