21042104207 has 4 divisors (see below), whose sum is σ = 21047014560. Its totient is φ = 21037193856.

The previous prime is 21042104159. The next prime is 21042104261. The reversal of 21042104207 is 70240124012.

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

It is a cyclic number.

It is not a de Polignac number, because 21042104207 - 2¹⁰ = 21042103183 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 (21042103207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2448743 + ... + 2457320.

It is an arithmetic number, because the mean of its divisors is an integer number (5261753640).

Almost surely, 2^21042104207 is an apocalyptic number.

21042104207 is a deficient number, since it is larger than the sum of its proper divisors (4910353).

21042104207 is an equidigital number, since it uses as much as digits as its factorization.

21042104207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4910352.

The product of its (nonzero) digits is 896, while the sum is 23.

Adding to 21042104207 its reverse (70240124012), we get a palindrome (91282228219).

The spelling of 21042104207 in words is "twenty-one billion, forty-two million, one hundred four thousand, two hundred seven".