20728755 has 24 divisors (see below), whose sum is σ = 36037872. Its totient is φ = 11022144.

The previous prime is 20728733. The next prime is 20728759. The reversal of 20728755 is 55782702.

It is not a de Polignac number, because 20728755 - 2⁶ = 20728691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20728759) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24652 + ... + 25478.

It is an arithmetic number, because the mean of its divisors is an integer number (1501578).

Almost surely, 2^20728755 is an apocalyptic number.

20728755 is a deficient number, since it is larger than the sum of its proper divisors (15309117).

20728755 is a wasteful number, since it uses less digits than its factorization.

20728755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1395 (or 1392 counting only the distinct ones).

The product of its (nonzero) digits is 39200, while the sum is 36.

The square root of 20728755 is about 4552.8842506701. The cubic root of 20728755 is about 274.6994181327.

The spelling of 20728755 in words is "twenty million, seven hundred twenty-eight thousand, seven hundred fifty-five".