647997 has 16 divisors (see below), whose sum is σ = 1006080. Its totient is φ = 363312.

The previous prime is 647987. The next prime is 648007. The reversal of 647997 is 799746.

It is an interprime number because it is at equal distance from previous prime (647987) and next prime (648007).

It is not a de Polignac number, because 647997 - 2⁸ = 647741 is a prime.

It is a super-2 number, since 2×647997² = 839800224018, which contains 22 as substring.

647997 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647917) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 978 + ... + 1500.

It is an arithmetic number, because the mean of its divisors is an integer number (62880).

2⁶⁴⁷⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

647997 is a deficient number, since it is larger than the sum of its proper divisors (358083).

647997 is a wasteful number, since it uses less digits than its factorization.

647997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592.

The product of its digits is 95256, while the sum is 42.

The square root of 647997 is about 804.9826085078. The cubic root of 647997 is about 86.5348406766.

The spelling of 647997 in words is "six hundred forty-seven thousand, nine hundred ninety-seven".