721663727 has 4 divisors (see below), whose sum is σ = 722339880. Its totient is φ = 720987576.

The previous prime is 721663717. The next prime is 721663777. The reversal of 721663727 is 727366127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 721663727 - 2¹⁰ = 721662703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721663717) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 336473 + ... + 338610.

It is an arithmetic number, because the mean of its divisors is an integer number (180584970).

Almost surely, 2^721663727 is an apocalyptic number.

721663727 is a deficient number, since it is larger than the sum of its proper divisors (676153).

721663727 is a wasteful number, since it uses less digits than its factorization.

721663727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676152.

The product of its digits is 148176, while the sum is 41.

The square root of 721663727 is about 26863.7995637252. The cubic root of 721663727 is about 896.9707732581.

The spelling of 721663727 in words is "seven hundred twenty-one million, six hundred sixty-three thousand, seven hundred twenty-seven".