20984809997 has 8 divisors (see below), whose sum is σ = 21071706360. Its totient is φ = 20898086400.

The previous prime is 20984809969. The next prime is 20984810009. The reversal of 20984809997 is 79990848902.

It can be written as a sum of positive squares in 4 ways, for example, as 2128681 + 20982681316 = 1459^2 + 144854^2 .

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 20984809997 - 2²² = 20980615693 is a prime.

It is a super-2 number, since 2×20984809997² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20984809907) 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, 203129 + ... + 288497.

It is an arithmetic number, because the mean of its divisors is an integer number (2633963295).

Almost surely, 2^20984809997 is an apocalyptic number.

It is an amenable number.

20984809997 is a deficient number, since it is larger than the sum of its proper divisors (86896363).

20984809997 is an equidigital number, since it uses as much as digits as its factorization.

20984809997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86383.

The product of its (nonzero) digits is 23514624, while the sum is 65.

The spelling of 20984809997 in words is "twenty billion, nine hundred eighty-four million, eight hundred nine thousand, nine hundred ninety-seven".