20081986951849 has 3 divisors (see below), whose sum is σ = 20081991433143. Its totient is φ = 20081982470556.

The previous prime is 20081986951847. The next prime is 20081986951861. The reversal of 20081986951849 is 94815968918002.

The square root of 20081986951849 is 4481293.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 8228206195225 + 11853780756624 = 2868485^2 + 3442932^2 .

It is not a de Polignac number, because 20081986951849 - 2¹ = 20081986951847 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20081986951843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2240647 + ... + 6721939.

It is an arithmetic number, because the mean of its divisors is an integer number (6693997144381).

Almost surely, 2^{20081986951849} is an apocalyptic number.

20081986951849 is the 4481293-rd square number.

20081986951849 is the 2240647-th centered octagonal number.

It is an amenable number.

20081986951849 is a deficient number, since it is larger than the sum of its proper divisors (4481294).

20081986951849 is an frugal number, since it uses more digits than its factorization.

20081986951849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8962586 (or 4481293 counting only the distinct ones).

The product of its (nonzero) digits is 89579520, while the sum is 70.

The spelling of 20081986951849 in words is "twenty trillion, eighty-one billion, nine hundred eighty-six million, nine hundred fifty-one thousand, eight hundred forty-nine".