20187389 has 4 divisors (see below), whose sum is σ = 20206080. Its totient is φ = 20168700.

The previous prime is 20187383. The next prime is 20187397. The reversal of 20187389 is 98378102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20187389 - 2⁴ = 20187373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20187383) 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, 7619 + ... + 9920.

It is an arithmetic number, because the mean of its divisors is an integer number (5051520).

Almost surely, 2^20187389 is an apocalyptic number.

It is an amenable number.

20187389 is a deficient number, since it is larger than the sum of its proper divisors (18691).

20187389 is a wasteful number, since it uses less digits than its factorization.

20187389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18690.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 20187389 is about 4493.0378364755. The cubic root of 20187389 is about 272.2868810328.

The spelling of 20187389 in words is "twenty million, one hundred eighty-seven thousand, three hundred eighty-nine".