20728090 has 8 divisors (see below), whose sum is σ = 37310580. Its totient is φ = 8291232.

The previous prime is 20728087. The next prime is 20728093. The reversal of 20728090 is 9082702.

It is an interprime number because it is at equal distance from previous prime (20728087) and next prime (20728093).

It can be written as a sum of positive squares in 2 ways, for example, as 19280881 + 1447209 = 4391^2 + 1203^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (20728093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1036395 + ... + 1036414.

Almost surely, 2^20728090 is an apocalyptic number.

20728090 is a deficient number, since it is larger than the sum of its proper divisors (16582490).

20728090 is a wasteful number, since it uses less digits than its factorization.

20728090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2072816.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 20728090 is about 4552.8112194555. The cubic root of 20728090 is about 274.6964805537.

The spelling of 20728090 in words is "twenty million, seven hundred twenty-eight thousand, ninety".