20538891 has 6 divisors (see below), whose sum is σ = 29667300. Its totient is φ = 13692588.

The previous prime is 20538871. The next prime is 20538893. The reversal of 20538891 is 19883502.

It is not a de Polignac number, because 20538891 - 2¹⁴ = 20522507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20538893) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1141041 + ... + 1141058.

It is an arithmetic number, because the mean of its divisors is an integer number (4944550).

Almost surely, 2^20538891 is an apocalyptic number.

20538891 is a deficient number, since it is larger than the sum of its proper divisors (9128409).

20538891 is a wasteful number, since it uses less digits than its factorization.

20538891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2282105 (or 2282102 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 20538891 is about 4531.9853265429. The cubic root of 20538891 is about 273.8581457992.

The spelling of 20538891 in words is "twenty million, five hundred thirty-eight thousand, eight hundred ninety-one".