660813440 has 64 divisors (see below), whose sum is σ = 1805448960. Its totient is φ = 226563072.

The previous prime is 660813431. The next prime is 660813449. The reversal of 660813440 is 44318066.

It is an interprime number because it is at equal distance from previous prime (660813431) and next prime (660813449).

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 660813397 and 660813406.

It is not an unprimeable number, because it can be changed into a prime (660813449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69272 + ... + 78231.

It is an arithmetic number, because the mean of its divisors is an integer number (28210140).

Almost surely, 2^660813440 is an apocalyptic number.

It is an amenable number.

660813440 is an abundant number, since it is smaller than the sum of its proper divisors (1144635520).

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

660813440 is a wasteful number, since it uses less digits than its factorization.

660813440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147529 (or 147517 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 660813440 is about 25706.2918368247. The cubic root of 660813440 is about 871.0163135153.

The spelling of 660813440 in words is "six hundred sixty million, eight hundred thirteen thousand, four hundred forty".