721889747 has 4 divisors (see below), whose sum is σ = 739496856. Its totient is φ = 704282640.

The previous prime is 721889711. The next prime is 721889767. The reversal of 721889747 is 747988127.

721889747 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 747988127 = 47 ⋅15914641.

It is a cyclic number.

It is not a de Polignac number, because 721889747 - 2¹⁶ = 721824211 is a prime.

It is a super-2 number, since 2×721889747² = 1042249613647448018, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721889767) 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, 8803493 + ... + 8803574.

It is an arithmetic number, because the mean of its divisors is an integer number (184874214).

Almost surely, 2^721889747 is an apocalyptic number.

721889747 is a deficient number, since it is larger than the sum of its proper divisors (17607109).

721889747 is a wasteful number, since it uses less digits than its factorization.

721889747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17607108.

The product of its digits is 1580544, while the sum is 53.

The square root of 721889747 is about 26868.0060108673. The cubic root of 721889747 is about 897.0644051282.

The spelling of 721889747 in words is "seven hundred twenty-one million, eight hundred eighty-nine thousand, seven hundred forty-seven".