660287981 has 8 divisors (see below), whose sum is σ = 695766720. Its totient is φ = 624881952.

The previous prime is 660287917. The next prime is 660287983. The reversal of 660287981 is 189782066.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 660287981 - 2⁶ = 660287917 is a prime.

It is a super-2 number, since 2×660287981² = 871960435706112722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660287983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1001 + ... + 36353.

It is an arithmetic number, because the mean of its divisors is an integer number (86970840).

Almost surely, 2^660287981 is an apocalyptic number.

It is an amenable number.

660287981 is a deficient number, since it is larger than the sum of its proper divisors (35478739).

660287981 is a wasteful number, since it uses less digits than its factorization.

660287981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36355.

The product of its (nonzero) digits is 290304, while the sum is 47.

The square root of 660287981 is about 25696.0693686797. The cubic root of 660287981 is about 870.7853836244.

The spelling of 660287981 in words is "six hundred sixty million, two hundred eighty-seven thousand, nine hundred eighty-one".