20902092809 has 8 divisors (see below), whose sum is σ = 23286151560. Its totient is φ = 18628920576.

The previous prime is 20902092791. The next prime is 20902092817. The reversal of 20902092809 is 90829020902.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 91145209 + 20810947600 = 9547^2 + 144260^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20902092809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20902092839) 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, 27721232 + ... + 27721985.

It is an arithmetic number, because the mean of its divisors is an integer number (2910768945).

Almost surely, 2^20902092809 is an apocalyptic number.

20902092809 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20902092809 is a deficient number, since it is larger than the sum of its proper divisors (2384058751).

20902092809 is a wasteful number, since it uses less digits than its factorization.

20902092809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55443259.

The product of its (nonzero) digits is 46656, while the sum is 41.

The spelling of 20902092809 in words is "twenty billion, nine hundred two million, ninety-two thousand, eight hundred nine".