21205234045 has 16 divisors (see below), whose sum is σ = 25632949248. Its totient is φ = 16839950400.

The previous prime is 21205233997. The next prime is 21205234051. The reversal of 21205234045 is 54043250212.

It is not a de Polignac number, because 21205234045 - 2²¹ = 21203136893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 840870 + ... + 865720.

It is an arithmetic number, because the mean of its divisors is an integer number (1602059328).

Almost surely, 2^21205234045 is an apocalyptic number.

It is an amenable number.

21205234045 is a deficient number, since it is larger than the sum of its proper divisors (4427715203).

21205234045 is a wasteful number, since it uses less digits than its factorization.

21205234045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26100.

The product of its (nonzero) digits is 9600, while the sum is 28.

Adding to 21205234045 its reverse (54043250212), we get a palindrome (75248484257).

The spelling of 21205234045 in words is "twenty-one billion, two hundred five million, two hundred thirty-four thousand, forty-five".