21042211145 has 4 divisors (see below), whose sum is σ = 25250653380. Its totient is φ = 16833768912.

The previous prime is 21042211087. The next prime is 21042211163. The reversal of 21042211145 is 54111224012.

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 3885402889 + 17156808256 = 62333^2 + 130984^2 .

It is a cyclic number.

It is not a de Polignac number, because 21042211145 - 2⁶ = 21042211081 is a prime.

It is a super-2 number, since 2×21042211145² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21042211145.

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, 2104221110 + ... + 2104221119.

It is an arithmetic number, because the mean of its divisors is an integer number (6312663345).

Almost surely, 2^21042211145 is an apocalyptic number.

It is an amenable number.

21042211145 is a deficient number, since it is larger than the sum of its proper divisors (4208442235).

21042211145 is an equidigital number, since it uses as much as digits as its factorization.

21042211145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4208442234.

The product of its (nonzero) digits is 640, while the sum is 23.

Adding to 21042211145 its reverse (54111224012), we get a palindrome (75153435157).

The spelling of 21042211145 in words is "twenty-one billion, forty-two million, two hundred eleven thousand, one hundred forty-five".