20538890 has 16 divisors (see below), whose sum is σ = 39145032. Its totient is φ = 7732224.

The previous prime is 20538871. The next prime is 20538893. The reversal of 20538890 is 9883502.

It can be written as a sum of positive squares in 4 ways, for example, as 19864849 + 674041 = 4457^2 + 821^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20538890.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60239 + ... + 60578.

Almost surely, 2^20538890 is an apocalyptic number.

20538890 is a deficient number, since it is larger than the sum of its proper divisors (18606142).

20538890 is a wasteful number, since it uses less digits than its factorization.

20538890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120841.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 20538890 is about 4531.9852162160. The cubic root of 20538890 is about 273.8581413547.

The spelling of 20538890 in words is "twenty million, five hundred thirty-eight thousand, eight hundred ninety".