20728413 has 16 divisors (see below), whose sum is σ = 30795840. Its totient is φ = 13779792.

The previous prime is 20728403. The next prime is 20728427. The reversal of 20728413 is 31482702.

It is not a de Polignac number, because 20728413 - 2⁹ = 20727901 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728403) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 11095 + ... + 12827.

It is an arithmetic number, because the mean of its divisors is an integer number (1924740).

Almost surely, 2^20728413 is an apocalyptic number.

It is an amenable number.

20728413 is a deficient number, since it is larger than the sum of its proper divisors (10067427).

20728413 is a wasteful number, since it uses less digits than its factorization.

20728413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2185 (or 2179 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20728413 is about 4552.8466919061. The cubic root of 20728413 is about 274.6979073856.

The spelling of 20728413 in words is "twenty million, seven hundred twenty-eight thousand, four hundred thirteen".