21054043205 has 16 divisors (see below), whose sum is σ = 27371240064. Its totient is φ = 15454493760.

The previous prime is 21054043201. The next prime is 21054043207. The reversal of 21054043205 is 50234045012.

It is a happy number.

It is not a de Polignac number, because 21054043205 - 2² = 21054043201 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 (21054043201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 958931 + ... + 980640.

It is an arithmetic number, because the mean of its divisors is an integer number (1710702504).

Almost surely, 2^21054043205 is an apocalyptic number.

It is an amenable number.

21054043205 is a deficient number, since it is larger than the sum of its proper divisors (6317196859).

21054043205 is a wasteful number, since it uses less digits than its factorization.

21054043205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939756.

The product of its (nonzero) digits is 4800, while the sum is 26.

Adding to 21054043205 its reverse (50234045012), we get a palindrome (71288088217).

The spelling of 21054043205 in words is "twenty-one billion, fifty-four million, forty-three thousand, two hundred five".