665680641 has 8 divisors (see below), whose sum is σ = 888209760. Its totient is φ = 443469312.

The previous prime is 665680621. The next prime is 665680643. The reversal of 665680641 is 146086566.

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

It is not a de Polignac number, because 665680641 - 2¹⁷ = 665549569 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 665680593 and 665680602.

It is not an unprimeable number, because it can be changed into a prime (665680643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74515 + ... + 82968.

It is an arithmetic number, because the mean of its divisors is an integer number (111026220).

Almost surely, 2^665680641 is an apocalyptic number.

It is an amenable number.

665680641 is a deficient number, since it is larger than the sum of its proper divisors (222529119).

665680641 is a wasteful number, since it uses less digits than its factorization.

665680641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158895.

The product of its (nonzero) digits is 207360, while the sum is 42.

The square root of 665680641 is about 25800.7876042574. The cubic root of 665680641 is about 873.1495658477.

The spelling of 665680641 in words is "six hundred sixty-five million, six hundred eighty thousand, six hundred forty-one".