20728419 has 4 divisors (see below), whose sum is σ = 27637896. Its totient is φ = 13818944.

The previous prime is 20728403. The next prime is 20728427. The reversal of 20728419 is 91482702.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20728419 - 2⁴ = 20728403 is a prime.

It is a super-2 number, since 2×20728419² = 859334708479122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20728419.

It is not an unprimeable number, because it can be changed into a prime (20728439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3454734 + ... + 3454739.

It is an arithmetic number, because the mean of its divisors is an integer number (6909474).

Almost surely, 2^20728419 is an apocalyptic number.

20728419 is a deficient number, since it is larger than the sum of its proper divisors (6909477).

20728419 is an equidigital number, since it uses as much as digits as its factorization.

20728419 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6909476.

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 20728419 is about 4552.8473508344. The cubic root of 20728419 is about 274.6979338901.

The spelling of 20728419 in words is "twenty million, seven hundred twenty-eight thousand, four hundred nineteen".