660781897 has 8 divisors (see below), whose sum is σ = 664018632. Its totient is φ = 657552000.

The previous prime is 660781861. The next prime is 660781921. The reversal of 660781897 is 798187066.

It can be written as a sum of positive squares in 4 ways, for example, as 86508601 + 574273296 = 9301^2 + 23964^2 .

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 660781897 - 2²³ = 652393289 is a prime.

It is a super-3 number, since 3×660781897³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660781837) 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, 346647 + ... + 348547.

It is an arithmetic number, because the mean of its divisors is an integer number (83002329).

Almost surely, 2^660781897 is an apocalyptic number.

It is an amenable number.

660781897 is a deficient number, since it is larger than the sum of its proper divisors (3236735).

660781897 is a wasteful number, since it uses less digits than its factorization.

660781897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3419.

The product of its (nonzero) digits is 1016064, while the sum is 52.

The square root of 660781897 is about 25705.6783026630. The cubic root of 660781897 is about 871.0024543819.

The spelling of 660781897 in words is "six hundred sixty million, seven hundred eighty-one thousand, eight hundred ninety-seven".