20438240279 has 4 divisors (see below), whose sum is σ = 20619109776. Its totient is φ = 20257370784.

The previous prime is 20438240213. The next prime is 20438240287. The reversal of 20438240279 is 97204283402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97204283402 = 2 ⋅48602141701.

It is not a de Polignac number, because 20438240279 - 2²⁰ = 20437191703 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 (20438240299) 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, 90434579 + ... + 90434804.

It is an arithmetic number, because the mean of its divisors is an integer number (5154777444).

Almost surely, 2^20438240279 is an apocalyptic number.

20438240279 is a deficient number, since it is larger than the sum of its proper divisors (180869497).

20438240279 is a wasteful number, since it uses less digits than its factorization.

20438240279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180869496.

The product of its (nonzero) digits is 193536, while the sum is 41.

The spelling of 20438240279 in words is "twenty billion, four hundred thirty-eight million, two hundred forty thousand, two hundred seventy-nine".