665100061 has 4 divisors (see below), whose sum is σ = 704223612. Its totient is φ = 625976512.

The previous prime is 665100053. The next prime is 665100067. The reversal of 665100061 is 160001566.

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

It can be written as a sum of positive squares in 2 ways, for example, as 304328025 + 360772036 = 17445^2 + 18994^2 .

It is a cyclic number.

It is not a de Polignac number, because 665100061 - 2³ = 665100053 is a prime.

It is a super-2 number, since 2×665100061² = 884716182284407442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 665099999 and 665100035.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665100067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19561750 + ... + 19561783.

It is an arithmetic number, because the mean of its divisors is an integer number (176055903).

Almost surely, 2^665100061 is an apocalyptic number.

It is an amenable number.

665100061 is a deficient number, since it is larger than the sum of its proper divisors (39123551).

665100061 is a wasteful number, since it uses less digits than its factorization.

665100061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39123550.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 665100061 is about 25789.5339430553. The cubic root of 665100061 is about 872.8956499853.

The spelling of 665100061 in words is "six hundred sixty-five million, one hundred thousand, sixty-one".