20728546 has 4 divisors (see below), whose sum is σ = 31092822. Its totient is φ = 10364272.

The previous prime is 20728531. The next prime is 20728549. The reversal of 20728546 is 64582702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 64582702 = 2 ⋅32291351.

It can be written as a sum of positive squares in only one way, i.e., 20602521 + 126025 = 4539^2 + 355^2 .

It is not an unprimeable number, because it can be changed into a prime (20728549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5182135 + ... + 5182138.

Almost surely, 2^20728546 is an apocalyptic number.

20728546 is a deficient number, since it is larger than the sum of its proper divisors (10364276).

20728546 is a wasteful number, since it uses less digits than its factorization.

20728546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10364275.

The product of its (nonzero) digits is 26880, while the sum is 34.

The square root of 20728546 is about 4552.8612981289. The cubic root of 20728546 is about 274.6984949003.

The spelling of 20728546 in words is "twenty million, seven hundred twenty-eight thousand, five hundred forty-six".