667728697 has 8 divisors (see below), whose sum is σ = 675866016. Its totient is φ = 659617152.

The previous prime is 667728667. The next prime is 667728727. The reversal of 667728697 is 796827766.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (667728667) and next prime (667728727).

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 667728697 - 2⁷ = 667728569 is a prime.

It is a super-2 number, since 2×667728697² = 891723225594635618, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (667728637) 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, 48498 + ... + 60724.

It is an arithmetic number, because the mean of its divisors is an integer number (84483252).

Almost surely, 2^667728697 is an apocalyptic number.

It is an amenable number.

667728697 is a deficient number, since it is larger than the sum of its proper divisors (8137319).

667728697 is a wasteful number, since it uses less digits than its factorization.

667728697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12887.

The product of its digits is 10668672, while the sum is 58.

The square root of 667728697 is about 25840.4469195097. The cubic root of 667728697 is about 874.0441031005.

The spelling of 667728697 in words is "six hundred sixty-seven million, seven hundred twenty-eight thousand, six hundred ninety-seven".