660840287 has 4 divisors (see below), whose sum is σ = 661366440. Its totient is φ = 660314136.

The previous prime is 660840281. The next prime is 660840289. The reversal of 660840287 is 782048066.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 660840287 - 2⁶ = 660840223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660840281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 261188 + ... + 263705.

It is an arithmetic number, because the mean of its divisors is an integer number (165341610).

Almost surely, 2^660840287 is an apocalyptic number.

660840287 is a deficient number, since it is larger than the sum of its proper divisors (526153).

660840287 is a wasteful number, since it uses less digits than its factorization.

660840287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526152.

The product of its (nonzero) digits is 129024, while the sum is 41.

The square root of 660840287 is about 25706.8140188550. The cubic root of 660840287 is about 871.0281090069.

The spelling of 660840287 in words is "six hundred sixty million, eight hundred forty thousand, two hundred eighty-seven".