728154661 has 4 divisors (see below), whose sum is σ = 784166572. Its totient is φ = 672142752.

The previous prime is 728154643. The next prime is 728154673. The reversal of 728154661 is 166451827.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166451827 = 283 ⋅588169.

It can be written as a sum of positive squares in 2 ways, for example, as 69205761 + 658948900 = 8319^2 + 25670^2 .

It is a cyclic number.

It is not a de Polignac number, because 728154661 - 2²⁷ = 593936933 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 (728154611) 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, 28005936 + ... + 28005961.

It is an arithmetic number, because the mean of its divisors is an integer number (196041643).

Almost surely, 2^728154661 is an apocalyptic number.

It is an amenable number.

728154661 is a deficient number, since it is larger than the sum of its proper divisors (56011911).

728154661 is a wasteful number, since it uses less digits than its factorization.

728154661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56011910.

The product of its digits is 80640, while the sum is 40.

The square root of 728154661 is about 26984.3410332734. The cubic root of 728154661 is about 899.6519893174.

The spelling of 728154661 in words is "seven hundred twenty-eight million, one hundred fifty-four thousand, six hundred sixty-one".