660728669 has 16 divisors (see below), whose sum is σ = 692936640. Its totient is φ = 629462400.

The previous prime is 660728633. The next prime is 660728671. The reversal of 660728669 is 966827066.

It is a cyclic number.

It is not a de Polignac number, because 660728669 - 2⁸ = 660728413 is a prime.

It is a super-2 number, since 2×660728669² = 873124748077023122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660728609) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 346619 + ... + 348519.

It is an arithmetic number, because the mean of its divisors is an integer number (43308540).

Almost surely, 2^660728669 is an apocalyptic number.

It is an amenable number.

660728669 is a deficient number, since it is larger than the sum of its proper divisors (32207971).

660728669 is a wasteful number, since it uses less digits than its factorization.

660728669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2140.

The product of its (nonzero) digits is 1306368, while the sum is 50.

The square root of 660728669 is about 25704.6429463628. The cubic root of 660728669 is about 870.9790664513.

The spelling of 660728669 in words is "six hundred sixty million, seven hundred twenty-eight thousand, six hundred sixty-nine".