20538791 has 24 divisors (see below), whose sum is σ = 27100080. Its totient is φ = 15386112.

The previous prime is 20538773. The next prime is 20538823. The reversal of 20538791 is 19783502.

It is not a de Polignac number, because 20538791 - 2¹⁰ = 20537767 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20538491) 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, 11255 + ... + 12951.

It is an arithmetic number, because the mean of its divisors is an integer number (1129170).

Almost surely, 2^20538791 is an apocalyptic number.

20538791 is a deficient number, since it is larger than the sum of its proper divisors (6561289).

20538791 is a wasteful number, since it uses less digits than its factorization.

20538791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1743 (or 1736 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 20538791 is about 4531.9742938371. The cubic root of 20538791 is about 273.8577013439.

The spelling of 20538791 in words is "twenty million, five hundred thirty-eight thousand, seven hundred ninety-one".