667780 has 24 divisors (see below), whose sum is σ = 1417752. Its totient is φ = 264192.

The previous prime is 667769. The next prime is 667781. The reversal of 667780 is 87766.

It can be written as a sum of positive squares in 4 ways, for example, as 114244 + 553536 = 338^2 + 744^2 .

It is not an unprimeable number, because it can be changed into a prime (667781) by changing a digit.

667780 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3364 + ... + 3556.

It is an arithmetic number, because the mean of its divisors is an integer number (59073).

2⁶⁶⁷⁷⁸⁰ is an apocalyptic number.

It is an amenable number.

667780 is an abundant number, since it is smaller than the sum of its proper divisors (749972).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

667780 is a wasteful number, since it uses less digits than its factorization.

667780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 34.

The square root of 667780 is about 817.1780711693. The cubic root of 667780 is about 87.4066487409.

The spelling of 667780 in words is "six hundred sixty-seven thousand, seven hundred eighty".