660699640 has 32 divisors (see below), whose sum is σ = 1506944880. Its totient is φ = 260658432.

The previous prime is 660699623. The next prime is 660699647. The reversal of 660699640 is 46996066.

It is a super-2 number, since 2×660699640² = 873048028592259200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660699647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110214 + ... + 116053.

Almost surely, 2^660699640 is an apocalyptic number.

It is an amenable number.

660699640 is an abundant number, since it is smaller than the sum of its proper divisors (846245240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

660699640 is a wasteful number, since it uses less digits than its factorization.

660699640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226351 (or 226347 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 46.

The square root of 660699640 is about 25704.0782756356. The cubic root of 660699640 is about 870.9663108262.

The spelling of 660699640 in words is "six hundred sixty million, six hundred ninety-nine thousand, six hundred forty".