665620461 has 12 divisors (see below), whose sum is σ = 1048856640. Its totient is φ = 403406280.

The previous prime is 665620451. The next prime is 665620469. The reversal of 665620461 is 164026566.

It is a happy number.

It is not a de Polignac number, because 665620461 - 2⁵ = 665620429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665620469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3361621 + ... + 3361818.

It is an arithmetic number, because the mean of its divisors is an integer number (87404720).

Almost surely, 2^665620461 is an apocalyptic number.

It is an amenable number.

665620461 is a deficient number, since it is larger than the sum of its proper divisors (383236179).

665620461 is a wasteful number, since it uses less digits than its factorization.

665620461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6723456 (or 6723453 counting only the distinct ones).

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

The square root of 665620461 is about 25799.6213344305. The cubic root of 665620461 is about 873.1232530679.

It can be divided in two parts, 665 and 620461, that added together give a palindrome (621126).

The spelling of 665620461 in words is "six hundred sixty-five million, six hundred twenty thousand, four hundred sixty-one".