647125291 has 4 divisors (see below), whose sum is σ = 648567000. Its totient is φ = 645683584.

The previous prime is 647125289. The next prime is 647125331. The reversal of 647125291 is 192521746.

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 647125291 - 2¹ = 647125289 is a prime.

It is a super-2 number, since 2×647125291² = 837542284503669362, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 647125291.

It is not an unprimeable number, because it can be changed into a prime (647125211) 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, 720181 + ... + 721078.

It is an arithmetic number, because the mean of its divisors is an integer number (162141750).

Almost surely, 2^647125291 is an apocalyptic number.

647125291 is a deficient number, since it is larger than the sum of its proper divisors (1441709).

647125291 is a wasteful number, since it uses less digits than its factorization.

647125291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441708.

The product of its digits is 30240, while the sum is 37.

The square root of 647125291 is about 25438.6574134721. The cubic root of 647125291 is about 864.9601999797.

The spelling of 647125291 in words is "six hundred forty-seven million, one hundred twenty-five thousand, two hundred ninety-one".