20728319 has 4 divisors (see below), whose sum is σ = 20748120. Its totient is φ = 20708520.

The previous prime is 20728291. The next prime is 20728339. The reversal of 20728319 is 91382702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91382702 = 2 ⋅45691351.

It is a cyclic number.

It is not a de Polignac number, because 20728319 - 2⁸ = 20728063 is a prime.

It is a super-2 number, since 2×20728319² = 859326417131522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728339) 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, 8237 + ... + 10454.

It is an arithmetic number, because the mean of its divisors is an integer number (5187030).

Almost surely, 2^20728319 is an apocalyptic number.

20728319 is a deficient number, since it is larger than the sum of its proper divisors (19801).

20728319 is a wasteful number, since it uses less digits than its factorization.

20728319 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19800.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 20728319 is about 4552.8363686827. The cubic root of 20728319 is about 274.6974921481.

The spelling of 20728319 in words is "twenty million, seven hundred twenty-eight thousand, three hundred nineteen".