647389 has 4 divisors (see below), whose sum is σ = 664924. Its totient is φ = 629856.

The previous prime is 647371. The next prime is 647399. The reversal of 647389 is 983746.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 983746 = 2 ⋅491873.

It can be written as a sum of positive squares in 2 ways, for example, as 235225 + 412164 = 485^2 + 642^2 .

It is a 5-Lehmer number, since φ(647389) divides (647389-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 647389 - 2⁵ = 647357 is a prime.

It is a super-2 number, since 2×647389² = 838225034642, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 17497 = 647389 / (6 + 4 + 7 + 3 + 8 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647359) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8712 + ... + 8785.

It is an arithmetic number, because the mean of its divisors is an integer number (166231).

2⁶⁴⁷³⁸⁹ is an apocalyptic number.

It is an amenable number.

647389 is a deficient number, since it is larger than the sum of its proper divisors (17535).

647389 is a wasteful number, since it uses less digits than its factorization.

647389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17534.

The product of its digits is 36288, while the sum is 37.

The square root of 647389 is about 804.6048719713. The cubic root of 647389 is about 86.5077676876.

The spelling of 647389 in words is "six hundred forty-seven thousand, three hundred eighty-nine".