20109523391 has 4 divisors (see below), whose sum is σ = 20364074400. Its totient is φ = 19854972384.

The previous prime is 20109523381. The next prime is 20109523409. The reversal of 20109523391 is 19332590102.

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 20109523391 - 2²⁶ = 20042414527 is a prime.

It is a super-2 number, since 2×20109523391² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20109523321) 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, 127275386 + ... + 127275543.

It is an arithmetic number, because the mean of its divisors is an integer number (5091018600).

Almost surely, 2^20109523391 is an apocalyptic number.

20109523391 is a deficient number, since it is larger than the sum of its proper divisors (254551009).

20109523391 is an equidigital number, since it uses as much as digits as its factorization.

20109523391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254551008.

The product of its (nonzero) digits is 14580, while the sum is 35.

The spelling of 20109523391 in words is "twenty billion, one hundred nine million, five hundred twenty-three thousand, three hundred ninety-one".