20728743 has 8 divisors (see below), whose sum is σ = 31586688. Its totient is φ = 11844984.

The previous prime is 20728733. The next prime is 20728759. The reversal of 20728743 is 34782702.

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

It is not a de Polignac number, because 20728743 - 2¹³ = 20720551 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728733) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 493521 + ... + 493562.

It is an arithmetic number, because the mean of its divisors is an integer number (3948336).

Almost surely, 2^20728743 is an apocalyptic number.

20728743 is a deficient number, since it is larger than the sum of its proper divisors (10857945).

20728743 is an equidigital number, since it uses as much as digits as its factorization.

20728743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 987093.

The product of its (nonzero) digits is 18816, while the sum is 33.

The square root of 20728743 is about 4552.8829328240. The cubic root of 20728743 is about 274.6993651243.

The spelling of 20728743 in words is "twenty million, seven hundred twenty-eight thousand, seven hundred forty-three".