20139911 has 4 divisors (see below), whose sum is σ = 21970824. Its totient is φ = 18309000.

The previous prime is 20139893. The next prime is 20139913. The reversal of 20139911 is 11993102.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20139911 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 (20139913) 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, 915440 + ... + 915461.

It is an arithmetic number, because the mean of its divisors is an integer number (5492706).

Almost surely, 2^20139911 is an apocalyptic number.

20139911 is a deficient number, since it is larger than the sum of its proper divisors (1830913).

20139911 is a wasteful number, since it uses less digits than its factorization.

20139911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1830912.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 20139911 is about 4487.7512185949. The cubic root of 20139911 is about 272.0732528698.

It can be divided in two parts, 20 and 139911, that added together give a palindrome (139931).

The spelling of 20139911 in words is "twenty million, one hundred thirty-nine thousand, nine hundred eleven".