647633509 has 4 divisors (see below), whose sum is σ = 654910380. Its totient is φ = 640356640.

The previous prime is 647633507. The next prime is 647633537. The reversal of 647633509 is 905336746.

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 244828609 + 402804900 = 15647^2 + 20070^2 .

It is a cyclic number.

It is not a de Polignac number, because 647633509 - 2¹ = 647633507 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647633507) 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, 3638302 + ... + 3638479.

It is an arithmetic number, because the mean of its divisors is an integer number (163727595).

Almost surely, 2^647633509 is an apocalyptic number.

It is an amenable number.

647633509 is a deficient number, since it is larger than the sum of its proper divisors (7276871).

647633509 is an equidigital number, since it uses as much as digits as its factorization.

647633509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7276870.

The product of its (nonzero) digits is 408240, while the sum is 43.

The square root of 647633509 is about 25448.6445415075. The cubic root of 647633509 is about 865.1865720711.

The spelling of 647633509 in words is "six hundred forty-seven million, six hundred thirty-three thousand, five hundred nine".