667795561 has 4 divisors (see below), whose sum is σ = 667888452. Its totient is φ = 667702672.

The previous prime is 667795553. The next prime is 667795567. The reversal of 667795561 is 165597766.

It is a happy number.

667795561 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.

It can be written as a sum of positive squares in 2 ways, for example, as 91795561 + 576000000 = 9581^2 + 24000^2 .

It is a cyclic number.

It is not a de Polignac number, because 667795561 - 2³ = 667795553 is a prime.

It is a super-2 number, since 2×667795561² = 891901822582609442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 667795499 and 667795508.

It is not an unprimeable number, because it can be changed into a prime (667795567) 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, 34666 + ... + 50371.

It is an arithmetic number, because the mean of its divisors is an integer number (166972113).

Almost surely, 2^667795561 is an apocalyptic number.

It is an amenable number.

667795561 is a deficient number, since it is larger than the sum of its proper divisors (92891).

667795561 is an equidigital number, since it uses as much as digits as its factorization.

667795561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92890.

The product of its digits is 2381400, while the sum is 52.

The square root of 667795561 is about 25841.7406727952. The cubic root of 667795561 is about 874.0732766927.

The spelling of 667795561 in words is "six hundred sixty-seven million, seven hundred ninety-five thousand, five hundred sixty-one".