728051661 has 6 divisors (see below), whose sum is σ = 1051630190. Its totient is φ = 485367768.

The previous prime is 728051659. The next prime is 728051677. The reversal of 728051661 is 166150827.

728051661 is a `hidden beast` number, since 7 + 2 + 80 + 516 + 61 = 666.

It can be written as a sum of positive squares in only one way, i.e., 727380900 + 670761 = 26970^2 + 819^2 .

It is not a de Polignac number, because 728051661 - 2¹ = 728051659 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 (728051161) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 40447306 + ... + 40447323.

Almost surely, 2^728051661 is an apocalyptic number.

It is an amenable number.

728051661 is a deficient number, since it is larger than the sum of its proper divisors (323578529).

728051661 is a wasteful number, since it uses less digits than its factorization.

728051661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80894635 (or 80894632 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 728051661 is about 26982.4324515044. The cubic root of 728051661 is about 899.6095676867.

The spelling of 728051661 in words is "seven hundred twenty-eight million, fifty-one thousand, six hundred sixty-one".