20639427 has 8 divisors (see below), whose sum is σ = 27540240. Its totient is φ = 13749120.

The previous prime is 20639407. The next prime is 20639471. The reversal of 20639427 is 72493602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20639427 - 2¹⁸ = 20377283 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20639407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6199 + ... + 8927.

It is an arithmetic number, because the mean of its divisors is an integer number (3442530).

Almost surely, 2^20639427 is an apocalyptic number.

20639427 is a deficient number, since it is larger than the sum of its proper divisors (6900813).

20639427 is a wasteful number, since it uses less digits than its factorization.

20639427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5253.

The product of its (nonzero) digits is 18144, while the sum is 33.

The square root of 20639427 is about 4543.0636139064. The cubic root of 20639427 is about 274.3042555903.

The spelling of 20639427 in words is "twenty million, six hundred thirty-nine thousand, four hundred twenty-seven".