21010431205 has 4 divisors (see below), whose sum is σ = 25212517452. Its totient is φ = 16808344960.

The previous prime is 21010431193. The next prime is 21010431217. The reversal of 21010431205 is 50213401012.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21010431193) and next prime (21010431217).

It can be written as a sum of positive squares in 2 ways, for example, as 11505351169 + 9505080036 = 107263^2 + 97494^2 .

It is not a de Polignac number, because 21010431205 - 2¹³ = 21010423013 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 3 ways as a sum of consecutive naturals, for example, 2101043116 + ... + 2101043125.

It is an arithmetic number, because the mean of its divisors is an integer number (6303129363).

Almost surely, 2^21010431205 is an apocalyptic number.

It is an amenable number.

21010431205 is a deficient number, since it is larger than the sum of its proper divisors (4202086247).

21010431205 is an equidigital number, since it uses as much as digits as its factorization.

21010431205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4202086246.

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21010431205 its reverse (50213401012), we get a palindrome (71223832217).

The spelling of 21010431205 in words is "twenty-one billion, ten million, four hundred thirty-one thousand, two hundred five".