728610721 has 8 divisors (see below), whose sum is σ = 763449984. Its totient is φ = 694034880.

The previous prime is 728610691. The next prime is 728610797. The reversal of 728610721 is 127016827.

It is a happy number.

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 728610721 - 2¹³ = 728602529 is a prime.

It is a super-2 number, since 2×728610721² = 1061747165512279682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (728610521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60181 + ... + 71266.

It is an arithmetic number, because the mean of its divisors is an integer number (95431248).

Almost surely, 2^728610721 is an apocalyptic number.

It is an amenable number.

728610721 is a deficient number, since it is larger than the sum of its proper divisors (34839263).

728610721 is a wasteful number, since it uses less digits than its factorization.

728610721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131711.

The product of its (nonzero) digits is 9408, while the sum is 34.

The square root of 728610721 is about 26992.7901670057. The cubic root of 728610721 is about 899.8397743576.

The spelling of 728610721 in words is "seven hundred twenty-eight million, six hundred ten thousand, seven hundred twenty-one".