721675649 has 8 divisors (see below), whose sum is σ = 725128992. Its totient is φ = 718230240.

The previous prime is 721675631. The next prime is 721675657. The reversal of 721675649 is 946576127.

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 721675649 - 2²⁰ = 720627073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721675609) 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 7 ways as a sum of consecutive naturals, for example, 252422 + ... + 255264.

It is an arithmetic number, because the mean of its divisors is an integer number (90641124).

Almost surely, 2^721675649 is an apocalyptic number.

It is an amenable number.

721675649 is a deficient number, since it is larger than the sum of its proper divisors (3453343).

721675649 is a wasteful number, since it uses less digits than its factorization.

721675649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3967.

The product of its digits is 635040, while the sum is 47.

The square root of 721675649 is about 26864.0214599378. The cubic root of 721675649 is about 896.9757125977.

The spelling of 721675649 in words is "seven hundred twenty-one million, six hundred seventy-five thousand, six hundred forty-nine".