647427917 has 4 divisors (see below), whose sum is σ = 648870300. Its totient is φ = 645985536.

The previous prime is 647427883. The next prime is 647427923. The reversal of 647427917 is 719724746.

It is a happy number.

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 349727401 + 297700516 = 18701^2 + 17254^2 .

It is a cyclic number.

It is not a de Polignac number, because 647427917 - 2²⁶ = 580319053 is a prime.

It is a super-3 number, since 3×647427917³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647427947) 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, 720518 + ... + 721415.

It is an arithmetic number, because the mean of its divisors is an integer number (162217575).

Almost surely, 2^647427917 is an apocalyptic number.

It is an amenable number.

647427917 is a deficient number, since it is larger than the sum of its proper divisors (1442383).

647427917 is a wasteful number, since it uses less digits than its factorization.

647427917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1442382.

The product of its digits is 592704, while the sum is 47.

The square root of 647427917 is about 25444.6048701881. The cubic root of 647427917 is about 865.0950108920.

The spelling of 647427917 in words is "six hundred forty-seven million, four hundred twenty-seven thousand, nine hundred seventeen".