21040031345 has 4 divisors (see below), whose sum is σ = 25248037620. Its totient is φ = 16832025072.

The previous prime is 21040031323. The next prime is 21040031393. The reversal of 21040031345 is 54313004012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4877485921 + 16162545424 = 69839^2 + 127132^2 .

It is a cyclic number.

It is not a de Polignac number, because 21040031345 - 2²⁴ = 21023254129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21040031345.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2104003130 + ... + 2104003139.

It is an arithmetic number, because the mean of its divisors is an integer number (6312009405).

Almost surely, 2^21040031345 is an apocalyptic number.

It is an amenable number.

21040031345 is a deficient number, since it is larger than the sum of its proper divisors (4208006275).

21040031345 is an equidigital number, since it uses as much as digits as its factorization.

21040031345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4208006274.

The product of its (nonzero) digits is 1440, while the sum is 23.

Adding to 21040031345 its reverse (54313004012), we get a palindrome (75353035357).

The spelling of 21040031345 in words is "twenty-one billion, forty million, thirty-one thousand, three hundred forty-five".