671605649 has 16 divisors (see below), whose sum is σ = 790655040. Its totient is φ = 562416960.

The previous prime is 671605643. The next prime is 671605657. The reversal of 671605649 is 946506176.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 671605649 - 2⁴ = 671605633 is a prime.

It is a super-2 number, since 2×671605649² = 902108295537422402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (671605643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68174 + ... + 77400.

It is an arithmetic number, because the mean of its divisors is an integer number (49415940).

Almost surely, 2^671605649 is an apocalyptic number.

It is an amenable number.

671605649 is a deficient number, since it is larger than the sum of its proper divisors (119049391).

671605649 is a wasteful number, since it uses less digits than its factorization.

671605649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9760.

The product of its (nonzero) digits is 272160, while the sum is 44.

The square root of 671605649 is about 25915.3554673672. The cubic root of 671605649 is about 875.7324583649.

The spelling of 671605649 in words is "six hundred seventy-one million, six hundred five thousand, six hundred forty-nine".