20984005181 has 4 divisors (see below), whose sum is σ = 21176519100. Its totient is φ = 20791491264.

The previous prime is 20984005157. The next prime is 20984005241. The reversal of 20984005181 is 18150048902.

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 18449788900 + 2534216281 = 135830^2 + 50341^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20984005181 is a prime.

It is a super-2 number, since 2×20984005181² (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 (20984005111) 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, 96256796 + ... + 96257013.

It is an arithmetic number, because the mean of its divisors is an integer number (5294129775).

Almost surely, 2^20984005181 is an apocalyptic number.

It is an amenable number.

20984005181 is a deficient number, since it is larger than the sum of its proper divisors (192513919).

20984005181 is a wasteful number, since it uses less digits than its factorization.

20984005181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192513918.

The product of its (nonzero) digits is 23040, while the sum is 38.

The spelling of 20984005181 in words is "twenty billion, nine hundred eighty-four million, five thousand, one hundred eighty-one".