21055023205 has 16 divisors (see below), whose sum is σ = 25316432064. Its totient is φ = 16810456960.

The previous prime is 21055023173. The next prime is 21055023221. The reversal of 21055023205 is 50232055012.

It is a happy number.

It is not a de Polignac number, because 21055023205 - 2⁵ = 21055023173 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21055023205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9286482 + ... + 9288748.

It is an arithmetic number, because the mean of its divisors is an integer number (1582277004).

Almost surely, 2^21055023205 is an apocalyptic number.

It is an amenable number.

21055023205 is a deficient number, since it is larger than the sum of its proper divisors (4261408859).

21055023205 is a wasteful number, since it uses less digits than its factorization.

21055023205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5156.

The product of its (nonzero) digits is 3000, while the sum is 25.

Adding to 21055023205 its reverse (50232055012), we get a palindrome (71287078217).

The spelling of 21055023205 in words is "twenty-one billion, fifty-five million, twenty-three thousand, two hundred five".