21232105205 has 16 divisors (see below), whose sum is σ = 27039613104. Its totient is φ = 15949578240.

The previous prime is 21232105187. The next prime is 21232105217. The reversal of 21232105205 is 50250123212.

It can be written as a sum of positive squares in 8 ways, for example, as 2115448036 + 19116657169 = 45994^2 + 138263^2 .

It is not a de Polignac number, because 21232105205 - 2¹⁰ = 21232104181 is a prime.

It is a Duffinian number.

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, 251636 + ... + 325245.

It is an arithmetic number, because the mean of its divisors is an integer number (1689975819).

Almost surely, 2^21232105205 is an apocalyptic number.

It is an amenable number.

21232105205 is a deficient number, since it is larger than the sum of its proper divisors (5807507899).

21232105205 is a wasteful number, since it uses less digits than its factorization.

21232105205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 577336.

The product of its (nonzero) digits is 1200, while the sum is 23.

Adding to 21232105205 its reverse (50250123212), we get a palindrome (71482228417).

The spelling of 21232105205 in words is "twenty-one billion, two hundred thirty-two million, one hundred five thousand, two hundred five".