666601645 has 8 divisors (see below), whose sum is σ = 800491104. Its totient is φ = 532901904.

The previous prime is 666601633. The next prime is 666601667. The reversal of 666601645 is 546106666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 666601645 - 2²¹ = 664504493 is a prime.

It is a super-3 number, since 3×666601645³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666601598 and 666601607.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 39579 + ... + 53848.

It is an arithmetic number, because the mean of its divisors is an integer number (100061388).

Almost surely, 2^666601645 is an apocalyptic number.

It is an amenable number.

666601645 is a deficient number, since it is larger than the sum of its proper divisors (133889459).

666601645 is a wasteful number, since it uses less digits than its factorization.

666601645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94859.

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 666601645 is about 25818.6298048522. The cubic root of 666601645 is about 873.5520629840.

The spelling of 666601645 in words is "six hundred sixty-six million, six hundred one thousand, six hundred forty-five".