647841890189 has 4 divisors (see below), whose sum is σ = 697675881756. Its totient is φ = 598007898624.

The previous prime is 647841890173. The next prime is 647841890209. The reversal of 647841890189 is 981098148746.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 981098148746 = 2 ⋅490549074373.

It can be written as a sum of positive squares in 2 ways, for example, as 139853560900 + 507988329289 = 373970^2 + 712733^2 .

It is a cyclic number.

It is not a de Polignac number, because 647841890189 - 2⁴ = 647841890173 is a prime.

It is a super-2 number, since 2×647841890189² (a number of 24 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 (647841890149) 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 3 ways as a sum of consecutive naturals, for example, 24916995764 + ... + 24916995789.

It is an arithmetic number, because the mean of its divisors is an integer number (174418970439).

Almost surely, 2^647841890189 is an apocalyptic number.

It is an amenable number.

647841890189 is a deficient number, since it is larger than the sum of its proper divisors (49833991567).

647841890189 is a wasteful number, since it uses less digits than its factorization.

647841890189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49833991566.

The product of its (nonzero) digits is 27869184, while the sum is 65.

The spelling of 647841890189 in words is "six hundred forty-seven billion, eight hundred forty-one million, eight hundred ninety thousand, one hundred eighty-nine".