20207639 has 4 divisors (see below), whose sum is σ = 21086256. Its totient is φ = 19329024.

The previous prime is 20207623. The next prime is 20207651. The reversal of 20207639 is 93670202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93670202 = 2 ⋅46835101.

It is a cyclic number.

It is not a de Polignac number, because 20207639 - 2⁴ = 20207623 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 (20207839) 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, 439274 + ... + 439319.

It is an arithmetic number, because the mean of its divisors is an integer number (5271564).

Almost surely, 2^20207639 is an apocalyptic number.

20207639 is a deficient number, since it is larger than the sum of its proper divisors (878617).

20207639 is an equidigital number, since it uses as much as digits as its factorization.

20207639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878616.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 20207639 is about 4495.2907581157. The cubic root of 20207639 is about 272.3778943998.

The spelling of 20207639 in words is "twenty million, two hundred seven thousand, six hundred thirty-nine".