21130405213 has 4 divisors (see below), whose sum is σ = 21348244540. Its totient is φ = 20912565888.

The previous prime is 21130405201. The next prime is 21130405237. The reversal of 21130405213 is 31250403112.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8861963044 + 12268442169 = 94138^2 + 110763^2 .

It is a cyclic number.

It is not a de Polignac number, because 21130405213 - 2¹⁷ = 21130274141 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 (21130405253) 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, 108919518 + ... + 108919711.

It is an arithmetic number, because the mean of its divisors is an integer number (5337061135).

Almost surely, 2^21130405213 is an apocalyptic number.

It is an amenable number.

21130405213 is a deficient number, since it is larger than the sum of its proper divisors (217839327).

21130405213 is an equidigital number, since it uses as much as digits as its factorization.

21130405213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217839326.

The product of its (nonzero) digits is 720, while the sum is 22.

Adding to 21130405213 its reverse (31250403112), we get a palindrome (52380808325).

The spelling of 21130405213 in words is "twenty-one billion, one hundred thirty million, four hundred five thousand, two hundred thirteen".