20928751 has 16 divisors (see below), whose sum is σ = 23113728. Its totient is φ = 18864000.

The previous prime is 20928707. The next prime is 20928757. The reversal of 20928751 is 15782902.

It is a cyclic number.

It is not a de Polignac number, because 20928751 - 2⁹ = 20928239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20928757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79446 + ... + 79708.

It is an arithmetic number, because the mean of its divisors is an integer number (1444608).

Almost surely, 2^20928751 is an apocalyptic number.

20928751 is a deficient number, since it is larger than the sum of its proper divisors (2184977).

20928751 is a wasteful number, since it uses less digits than its factorization.

20928751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 462.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 20928751 is about 4574.7951866723. The cubic root of 20928751 is about 275.5800472929.

The spelling of 20928751 in words is "twenty million, nine hundred twenty-eight thousand, seven hundred fifty-one".