665145851 has 4 divisors (see below), whose sum is σ = 674257512. Its totient is φ = 656034192.

The previous prime is 665145841. The next prime is 665145853. The reversal of 665145851 is 158541566.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665145851 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665145799 and 665145808.

It is not an unprimeable number, because it can be changed into a prime (665145853) 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, 4555721 + ... + 4555866.

It is an arithmetic number, because the mean of its divisors is an integer number (168564378).

Almost surely, 2^665145851 is an apocalyptic number.

665145851 is a deficient number, since it is larger than the sum of its proper divisors (9111661).

665145851 is an equidigital number, since it uses as much as digits as its factorization.

665145851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9111660.

The product of its digits is 144000, while the sum is 41.

The square root of 665145851 is about 25790.4216910077. The cubic root of 665145851 is about 872.9156815450.

The spelling of 665145851 in words is "six hundred sixty-five million, one hundred forty-five thousand, eight hundred fifty-one".