664181847 has 24 divisors (see below), whose sum is σ = 1114407840. Its totient is φ = 373308480.

The previous prime is 664181831. The next prime is 664181897. The reversal of 664181847 is 748181466.

It is not a de Polignac number, because 664181847 - 2⁴ = 664181831 is a prime.

It is a super-2 number, since 2×664181847² = 882275051768662818, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664181897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 82572 + ... + 90257.

It is an arithmetic number, because the mean of its divisors is an integer number (46433660).

Almost surely, 2^664181847 is an apocalyptic number.

664181847 is a deficient number, since it is larger than the sum of its proper divisors (450225993).

664181847 is a wasteful number, since it uses less digits than its factorization.

664181847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172903 (or 172900 counting only the distinct ones).

The product of its digits is 258048, while the sum is 45.

The square root of 664181847 is about 25771.7257280144. The cubic root of 664181847 is about 872.4937685343.

It can be divided in two parts, 66418 and 1847, that added together give a triangular number (68265 = T₃₆₉).

The spelling of 664181847 in words is "six hundred sixty-four million, one hundred eighty-one thousand, eight hundred forty-seven".