20928591 has 16 divisors (see below), whose sum is σ = 31098720. Its totient is φ = 13910400.

The previous prime is 20928541. The next prime is 20928629. The reversal of 20928591 is 19582902.

It is not a de Polignac number, because 20928591 - 2⁶ = 20928527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20928511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9861 + ... + 11793.

It is an arithmetic number, because the mean of its divisors is an integer number (1943670).

Almost surely, 2^20928591 is an apocalyptic number.

20928591 is a deficient number, since it is larger than the sum of its proper divisors (10170129).

20928591 is a wasteful number, since it uses less digits than its factorization.

20928591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2343 (or 2337 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 20928591 is about 4574.7776995172. Note that the first 3 decimals coincide. The cubic root of 20928591 is about 275.5793450226.

The spelling of 20928591 in words is "twenty million, nine hundred twenty-eight thousand, five hundred ninety-one".