661673649 has 32 divisors (see below), whose sum is σ = 1103651584. Its totient is φ = 343284480.

The previous prime is 661673611. The next prime is 661673653. The reversal of 661673649 is 946376166.

661673649 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 661673649 - 2⁷ = 661673521 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 661673598 and 661673607.

It is not an unprimeable number, because it can be changed into a prime (661673669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3214 + ... + 36519.

It is an arithmetic number, because the mean of its divisors is an integer number (34489112).

Almost surely, 2^661673649 is an apocalyptic number.

It is an amenable number.

661673649 is a deficient number, since it is larger than the sum of its proper divisors (441977935).

661673649 is a wasteful number, since it uses less digits than its factorization.

661673649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39817.

The product of its digits is 979776, while the sum is 48.

The square root of 661673649 is about 25723.0178828224. The cubic root of 661673649 is about 871.3940959819.

The spelling of 661673649 in words is "six hundred sixty-one million, six hundred seventy-three thousand, six hundred forty-nine".