647564643731 has 4 divisors (see below), whose sum is σ = 647589703992. Its totient is φ = 647539583472.

The previous prime is 647564643689. The next prime is 647564643751. The reversal of 647564643731 is 137346465746.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 647564643731 - 2⁶ = 647564643667 is a prime.

It is a super-2 number, since 2×647564643731² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (647564643751) 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, 12491330 + ... + 12543063.

It is an arithmetic number, because the mean of its divisors is an integer number (161897425998).

Almost surely, 2^647564643731 is an apocalyptic number.

647564643731 is a deficient number, since it is larger than the sum of its proper divisors (25060261).

647564643731 is a wasteful number, since it uses less digits than its factorization.

647564643731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25060260.

The product of its digits is 30481920, while the sum is 56.

The spelling of 647564643731 in words is "six hundred forty-seven billion, five hundred sixty-four million, six hundred forty-three thousand, seven hundred thirty-one".