666561460 has 24 divisors (see below), whose sum is σ = 1407520296. Its totient is φ = 265150080.

The previous prime is 666561431. The next prime is 666561481. The reversal of 666561460 is 64165666.

It can be written as a sum of positive squares in 4 ways, for example, as 14167696 + 652393764 = 3764^2 + 25542^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88447 + ... + 95686.

It is an arithmetic number, because the mean of its divisors is an integer number (58646679).

Almost surely, 2^666561460 is an apocalyptic number.

It is an amenable number.

666561460 is an abundant number, since it is smaller than the sum of its proper divisors (740958836).

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

666561460 is a wasteful number, since it uses less digits than its factorization.

666561460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184323 (or 184321 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 666561460 is about 25817.8515759929. The cubic root of 666561460 is about 873.5345090744.

The spelling of 666561460 in words is "six hundred sixty-six million, five hundred sixty-one thousand, four hundred sixty".