660640424 has 8 divisors (see below), whose sum is σ = 1238700810. Its totient is φ = 330320208.

The previous prime is 660640381. The next prime is 660640427. The reversal of 660640424 is 424046066.

It can be written as a sum of positive squares in only one way, i.e., 570732100 + 89908324 = 23890^2 + 9482^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (660640427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41290019 + ... + 41290034.

Almost surely, 2^660640424 is an apocalyptic number.

It is an amenable number.

660640424 is a deficient number, since it is larger than the sum of its proper divisors (578060386).

660640424 is a wasteful number, since it uses less digits than its factorization.

660640424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82580059 (or 82580055 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 660640424 is about 25702.9263703571. The cubic root of 660640424 is about 870.9402895810.

The spelling of 660640424 in words is "six hundred sixty million, six hundred forty thousand, four hundred twenty-four".