20728875 has 32 divisors (see below), whose sum is σ = 34804224. Its totient is φ = 10956000.

The previous prime is 20728859. The next prime is 20728891. The reversal of 20728875 is 57882702.

20728875 = 266² + 267² + ... + 432².

It is an interprime number because it is at equal distance from previous prime (20728859) and next prime (20728891).

It is not a de Polignac number, because 20728875 - 2⁴ = 20728859 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 62460 + ... + 62790.

It is an arithmetic number, because the mean of its divisors is an integer number (1087632).

Almost surely, 2^20728875 is an apocalyptic number.

20728875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20728875 is a deficient number, since it is larger than the sum of its proper divisors (14075349).

20728875 is a wasteful number, since it uses less digits than its factorization.

20728875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516 (or 506 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 39.

The square root of 20728875 is about 4552.8974291104. The cubic root of 20728875 is about 274.6999482154.

The spelling of 20728875 in words is "twenty million, seven hundred twenty-eight thousand, eight hundred seventy-five".