671647 has 2 divisors, whose sum is σ = 671648. Its totient is φ = 671646.

The previous prime is 671633. The next prime is 671651. The reversal of 671647 is 746176.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 671647 - 2⁷ = 671519 is a prime.

It is a super-2 number, since 2×671647² = 902219385218, which contains 22 as substring.

It is a plaindrome in base 14.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (671947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 335823 + 335824.

It is an arithmetic number, because the mean of its divisors is an integer number (335824).

2⁶⁷¹⁶⁴⁷ is an apocalyptic number.

671647 is a deficient number, since it is larger than the sum of its proper divisors (1).

671647 is an equidigital number, since it uses as much as digits as its factorization.

671647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 31.

The square root of 671647 is about 819.5407250406. The cubic root of 671647 is about 87.5750431050.

Subtracting 671647 from its reverse (746176), we obtain a square (74529 = 273²).

The spelling of 671647 in words is "six hundred seventy-one thousand, six hundred forty-seven".