665206641 has 16 divisors (see below), whose sum is σ = 1075081920. Its totient is φ = 403155360.

The previous prime is 665206613. The next prime is 665206687. The reversal of 665206641 is 146602566.

It is a happy number.

665206641 is a `hidden beast` number, since 6 + 6 + 5 + 2 + 0 + 6 + 641 = 666.

It is not a de Polignac number, because 665206641 - 2¹⁷ = 665075569 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 665206596 and 665206605.

It is not an unprimeable number, because it can be changed into a prime (665206741) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1119580 + ... + 1120173.

It is an arithmetic number, because the mean of its divisors is an integer number (67192620).

Almost surely, 2^665206641 is an apocalyptic number.

It is an amenable number.

665206641 is a deficient number, since it is larger than the sum of its proper divisors (409875279).

665206641 is a wasteful number, since it uses less digits than its factorization.

665206641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2239773 (or 2239767 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 665206641 is about 25791.6002023915. The cubic root of 665206641 is about 872.9422736714.

The spelling of 665206641 in words is "six hundred sixty-five million, two hundred six thousand, six hundred forty-one".