647641146691 has 54 divisors (see below), whose sum is σ = 831380099004. Its totient is φ = 502659788400.

The previous prime is 647641146631. The next prime is 647641146709. The reversal of 647641146691 is 196641146746.

647641146691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-647641146691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (647641146631) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 798570676 + ... + 798571486.

Almost surely, 2^647641146691 is an apocalyptic number.

647641146691 is a deficient number, since it is larger than the sum of its proper divisors (183738952313).

647641146691 is an equidigital number, since it uses as much as digits as its factorization.

647641146691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1581 (or 1196 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 55.

Adding to 647641146691 its sum of digits (55), we get a palindrome (647641146746).

The spelling of 647641146691 in words is "six hundred forty-seven billion, six hundred forty-one million, one hundred forty-six thousand, six hundred ninety-one".