20728011 has 16 divisors (see below), whose sum is σ = 28922400. Its totient is φ = 13187328.

The previous prime is 20728009. The next prime is 20728033. The reversal of 20728011 is 11082702.

It is not a de Polignac number, because 20728011 - 2¹ = 20728009 is a prime.

It is a super-2 number, since 2×20728011² = 859300880032242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20728061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6405 + ... + 9081.

It is an arithmetic number, because the mean of its divisors is an integer number (1807650).

Almost surely, 2^20728011 is an apocalyptic number.

20728011 is a deficient number, since it is larger than the sum of its proper divisors (8194389).

20728011 is a wasteful number, since it uses less digits than its factorization.

20728011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2798.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 20728011 is about 4552.8025434890. The cubic root of 20728011 is about 274.6961315740.

The spelling of 20728011 in words is "twenty million, seven hundred twenty-eight thousand, eleven".