20389939 has 4 divisors (see below), whose sum is σ = 20409624. Its totient is φ = 20370256.

The previous prime is 20389927. The next prime is 20389951. The reversal of 20389939 is 93998302.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93998302 = 2 ⋅46999151.

It is an interprime number because it is at equal distance from previous prime (20389927) and next prime (20389951).

It is a cyclic number.

It is not a de Polignac number, because 20389939 - 2¹⁵ = 20357171 is a prime.

It is a super-2 number, since 2×20389939² = 831499224847442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20389895 and 20389904.

It is not an unprimeable number, because it can be changed into a prime (20381939) 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 3 ways as a sum of consecutive naturals, for example, 8197 + ... + 10390.

It is an arithmetic number, because the mean of its divisors is an integer number (5102406).

Almost surely, 2^20389939 is an apocalyptic number.

20389939 is a deficient number, since it is larger than the sum of its proper divisors (19685).

20389939 is a wasteful number, since it uses less digits than its factorization.

20389939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19684.

The product of its (nonzero) digits is 104976, while the sum is 43.

The square root of 20389939 is about 4515.5220074760. The cubic root of 20389939 is about 273.1945149088.

The spelling of 20389939 in words is "twenty million, three hundred eighty-nine thousand, nine hundred thirty-nine".