20445364391 has 4 divisors (see below), whose sum is σ = 20880372192. Its totient is φ = 20010356592.

The previous prime is 20445364351. The next prime is 20445364397. The reversal of 20445364391 is 19346354402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19346354402 = 2 ⋅9673177201.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20445364391 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 (20445364397) 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, 217503830 + ... + 217503923.

It is an arithmetic number, because the mean of its divisors is an integer number (5220093048).

Almost surely, 2^20445364391 is an apocalyptic number.

20445364391 is a deficient number, since it is larger than the sum of its proper divisors (435007801).

20445364391 is an equidigital number, since it uses as much as digits as its factorization.

20445364391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435007800.

The product of its (nonzero) digits is 311040, while the sum is 41.

The spelling of 20445364391 in words is "twenty billion, four hundred forty-five million, three hundred sixty-four thousand, three hundred ninety-one".