721889727 has 8 divisors (see below), whose sum is σ = 1036559664. Its totient is φ = 444239808.

The previous prime is 721889711. The next prime is 721889767. The reversal of 721889727 is 727988127.

It is a happy number.

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

It is not a de Polignac number, because 721889727 - 2⁴ = 721889711 is a prime.

It is a super-2 number, since 2×721889727² = 1042249555896269058, which contains 22 as substring.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 721889727.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721889767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9254958 + ... + 9255035.

It is an arithmetic number, because the mean of its divisors is an integer number (129569958).

Almost surely, 2^721889727 is an apocalyptic number.

721889727 is a deficient number, since it is larger than the sum of its proper divisors (314669937).

721889727 is a wasteful number, since it uses less digits than its factorization.

721889727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18510009.

The product of its digits is 790272, while the sum is 51.

The square root of 721889727 is about 26868.0056386774. The cubic root of 721889727 is about 897.0643968438.

The spelling of 721889727 in words is "seven hundred twenty-one million, eight hundred eighty-nine thousand, seven hundred twenty-seven".