667728019 has 8 divisors (see below), whose sum is σ = 796296960. Its totient is φ = 547453896.

The previous prime is 667727993. The next prime is 667728031. The reversal of 667728019 is 910827766.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 667728019 - 2¹⁷ = 667596947 is a prime.

It is a super-2 number, since 2×667728019² = 891721414715328722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 667728019.

It is not an unprimeable number, because it can be changed into a prime (667728049) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2073529 + ... + 2073850.

It is an arithmetic number, because the mean of its divisors is an integer number (99537120).

Almost surely, 2^667728019 is an apocalyptic number.

667728019 is a deficient number, since it is larger than the sum of its proper divisors (128568941).

667728019 is a wasteful number, since it uses less digits than its factorization.

667728019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4147409.

The product of its (nonzero) digits is 254016, while the sum is 46.

The square root of 667728019 is about 25840.4338005383. The cubic root of 667728019 is about 874.0438072707.

The spelling of 667728019 in words is "six hundred sixty-seven million, seven hundred twenty-eight thousand, nineteen".