20388671 has 4 divisors (see below), whose sum is σ = 20436192. Its totient is φ = 20341152.

The previous prime is 20388583. The next prime is 20388727. The reversal of 20388671 is 17688302.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20388671 - 2¹⁸ = 20126527 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 (20388371) 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, 23111 + ... + 23976.

It is an arithmetic number, because the mean of its divisors is an integer number (5109048).

Almost surely, 2^20388671 is an apocalyptic number.

20388671 is a deficient number, since it is larger than the sum of its proper divisors (47521).

20388671 is an equidigital number, since it uses as much as digits as its factorization.

20388671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47520.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 20388671 is about 4515.3816007066. The cubic root of 20388671 is about 273.1888516938.

The spelling of 20388671 in words is "twenty million, three hundred eighty-eight thousand, six hundred seventy-one".