647639249 has 4 divisors (see below), whose sum is σ = 647738880. Its totient is φ = 647539620.

The previous prime is 647639243. The next prime is 647639269. The reversal of 647639249 is 942936746.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 942936746 = 2 ⋅471468373.

It is a cyclic number.

It is not a de Polignac number, because 647639249 - 2⁴ = 647639233 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 647639197 and 647639206.

It is not an unprimeable number, because it can be changed into a prime (647639243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39329 + ... + 53310.

It is an arithmetic number, because the mean of its divisors is an integer number (161934720).

Almost surely, 2^647639249 is an apocalyptic number.

It is an amenable number.

647639249 is a deficient number, since it is larger than the sum of its proper divisors (99631).

647639249 is an equidigital number, since it uses as much as digits as its factorization.

647639249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99630.

The product of its digits is 1959552, while the sum is 50.

The square root of 647639249 is about 25448.7573174016. The cubic root of 647639249 is about 865.1891281239.

The spelling of 647639249 in words is "six hundred forty-seven million, six hundred thirty-nine thousand, two hundred forty-nine".