660011640 has 128 divisors (see below), whose sum is σ = 2031644160. Its totient is φ = 171477504.

The previous prime is 660011633. The next prime is 660011641. The reversal of 660011640 is 46110066.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 660011640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660011641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 827722 + ... + 828518.

It is an arithmetic number, because the mean of its divisors is an integer number (15872220).

Almost surely, 2^660011640 is an apocalyptic number.

660011640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 660011640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1015822080).

660011640 is an abundant number, since it is smaller than the sum of its proper divisors (1371632520).

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

660011640 is a wasteful number, since it uses less digits than its factorization.

660011640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 981 (or 977 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 660011640 is about 25690.6916995242. The cubic root of 660011640 is about 870.6638875055.

The spelling of 660011640 in words is "six hundred sixty million, eleven thousand, six hundred forty".