665167819 has 2 divisors, whose sum is σ = 665167820. Its totient is φ = 665167818.

The previous prime is 665167807. The next prime is 665167859. The reversal of 665167819 is 918761566.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665167819 - 2⁵ = 665167787 is a prime.

It is a super-2 number, since 2×665167819² = 884896454866433522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (665167859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332583909 + 332583910.

It is an arithmetic number, because the mean of its divisors is an integer number (332583910).

Almost surely, 2^665167819 is an apocalyptic number.

665167819 is a deficient number, since it is larger than the sum of its proper divisors (1).

665167819 is an equidigital number, since it uses as much as digits as its factorization.

665167819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 544320, while the sum is 49.

The square root of 665167819 is about 25790.8475820396. The cubic root of 665167819 is about 872.9252914676.

The spelling of 665167819 in words is "six hundred sixty-five million, one hundred sixty-seven thousand, eight hundred nineteen".