20387389 has 4 divisors (see below), whose sum is σ = 22240800. Its totient is φ = 18533980.

The previous prime is 20387387. The next prime is 20387401. The reversal of 20387389 is 98378302.

It is a happy number.

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 20387389 - 2¹ = 20387387 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20387383) 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, 926689 + ... + 926710.

It is an arithmetic number, because the mean of its divisors is an integer number (5560200).

Almost surely, 2^20387389 is an apocalyptic number.

It is an amenable number.

20387389 is a deficient number, since it is larger than the sum of its proper divisors (1853411).

20387389 is a wasteful number, since it uses less digits than its factorization.

20387389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1853410.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 20387389 is about 4515.2396392661. The cubic root of 20387389 is about 273.1831257125.

The spelling of 20387389 in words is "twenty million, three hundred eighty-seven thousand, three hundred eighty-nine".