20145887 has 4 divisors (see below), whose sum is σ = 20614440. Its totient is φ = 19677336.

The previous prime is 20145863. The next prime is 20145889. The reversal of 20145887 is 78854102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78854102 = 2 ⋅39427051.

It is a cyclic number.

It is not a de Polignac number, because 20145887 - 2¹⁴ = 20129503 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20145889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 234212 + ... + 234297.

It is an arithmetic number, because the mean of its divisors is an integer number (5153610).

Almost surely, 2^20145887 is an apocalyptic number.

20145887 is a deficient number, since it is larger than the sum of its proper divisors (468553).

20145887 is an equidigital number, since it uses as much as digits as its factorization.

20145887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468552.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 20145887 is about 4488.4169815203. The cubic root of 20145887 is about 272.1001604527.

Adding to 20145887 its reverse (78854102), we get a palindrome (98999989).

The spelling of 20145887 in words is "twenty million, one hundred forty-five thousand, eight hundred eighty-seven".