665664431 has 4 divisors (see below), whose sum is σ = 679827552. Its totient is φ = 651501312.

The previous prime is 665664409. The next prime is 665664451. The reversal of 665664431 is 134466566.

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-665664431 is a prime.

It is a super-2 number, since 2×665664431² = 886218269397107522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665664451) 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, 7081490 + ... + 7081583.

It is an arithmetic number, because the mean of its divisors is an integer number (169956888).

Almost surely, 2^665664431 is an apocalyptic number.

665664431 is a deficient number, since it is larger than the sum of its proper divisors (14163121).

665664431 is a wasteful number, since it uses less digits than its factorization.

665664431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14163120.

The product of its digits is 311040, while the sum is 41.

The square root of 665664431 is about 25800.4734646479. The cubic root of 665664431 is about 873.1424784304.

The spelling of 665664431 in words is "six hundred sixty-five million, six hundred sixty-four thousand, four hundred thirty-one".