20728478 has 4 divisors (see below), whose sum is σ = 31092720. Its totient is φ = 10364238.

The previous prime is 20728469. The next prime is 20728481. The reversal of 20728478 is 87482702.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5182118 + ... + 5182121.

It is an arithmetic number, because the mean of its divisors is an integer number (7773180).

Almost surely, 2^20728478 is an apocalyptic number.

20728478 is a deficient number, since it is larger than the sum of its proper divisors (10364242).

20728478 is a wasteful number, since it uses less digits than its factorization.

20728478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10364241.

The product of its (nonzero) digits is 50176, while the sum is 38.

The square root of 20728478 is about 4552.8538302915. The cubic root of 20728478 is about 274.6981945172.

The spelling of 20728478 in words is "twenty million, seven hundred twenty-eight thousand, four hundred seventy-eight".