667997 has 4 divisors (see below), whose sum is σ = 728736. Its totient is φ = 607260.

The previous prime is 667991. The next prime is 667999. The reversal of 667997 is 799766.

667997 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 667997 - 2⁸ = 667741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667991) 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, 30353 + ... + 30374.

It is an arithmetic number, because the mean of its divisors is an integer number (182184).

2⁶⁶⁷⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

667997 is a deficient number, since it is larger than the sum of its proper divisors (60739).

667997 is a wasteful number, since it uses less digits than its factorization.

667997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60738.

The product of its digits is 142884, while the sum is 44.

The square root of 667997 is about 817.3108343831. The cubic root of 667997 is about 87.4161155257.

Subtracting 667997 from its reverse (799766), we obtain a square (131769 = 363²).

It can be divided in two parts, 6679 and 97, that added together give a palindrome (6776).

The spelling of 667997 in words is "six hundred sixty-seven thousand, nine hundred ninety-seven".