973428721 has 4 divisors (see below), whose sum is σ = 1030689252. Its totient is φ = 916168192.

The previous prime is 973428713. The next prime is 973428733. The reversal of 973428721 is 127824379.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127824379 = 1019 ⋅125441.

It can be written as a sum of positive squares in 2 ways, for example, as 914215696 + 59213025 = 30236^2 + 7695^2 .

It is a cyclic number.

It is not a de Polignac number, because 973428721 - 2³ = 973428713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (973428791) 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, 28630240 + ... + 28630273.

It is an arithmetic number, because the mean of its divisors is an integer number (257672313).

Almost surely, 2^973428721 is an apocalyptic number.

It is an amenable number.

973428721 is a deficient number, since it is larger than the sum of its proper divisors (57260531).

973428721 is a wasteful number, since it uses less digits than its factorization.

973428721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57260530.

The product of its digits is 169344, while the sum is 43.

The square root of 973428721 is about 31199.8192462713. The cubic root of 973428721 is about 991.0632799449.

The spelling of 973428721 in words is "nine hundred seventy-three million, four hundred twenty-eight thousand, seven hundred twenty-one".