665679651 has 40 divisors (see below), whose sum is σ = 1115246160. Its totient is φ = 351078336.

The previous prime is 665679643. The next prime is 665679653. The reversal of 665679651 is 156976566.

It is not a de Polignac number, because 665679651 - 2³ = 665679643 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 665679594 and 665679603.

It is not an unprimeable number, because it can be changed into a prime (665679653) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 90085 + ... + 97193.

It is an arithmetic number, because the mean of its divisors is an integer number (27881154).

Almost surely, 2^665679651 is an apocalyptic number.

665679651 is a deficient number, since it is larger than the sum of its proper divisors (449566509).

665679651 is an equidigital number, since it uses as much as digits as its factorization.

665679651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7153 (or 7132 counting only the distinct ones).

The product of its digits is 2041200, while the sum is 51.

The square root of 665679651 is about 25800.7684187894. The cubic root of 665679651 is about 873.1491329982.

The spelling of 665679651 in words is "six hundred sixty-five million, six hundred seventy-nine thousand, six hundred fifty-one".