20440139 has 4 divisors (see below), whose sum is σ = 20825856. Its totient is φ = 20054424.

The previous prime is 20440111. The next prime is 20440151. The reversal of 20440139 is 93104402.

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 20440139 - 2¹⁶ = 20374603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20440109) 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, 192779 + ... + 192884.

It is an arithmetic number, because the mean of its divisors is an integer number (5206464).

Almost surely, 2^20440139 is an apocalyptic number.

20440139 is a deficient number, since it is larger than the sum of its proper divisors (385717).

20440139 is an equidigital number, since it uses as much as digits as its factorization.

20440139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385716.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 20440139 is about 4521.0771946517. The cubic root of 20440139 is about 273.4185326642.

The spelling of 20440139 in words is "twenty million, four hundred forty thousand, one hundred thirty-nine".