21530412213 has 4 divisors (see below), whose sum is σ = 28707216288. Its totient is φ = 14353608140.

The previous prime is 21530412209. The next prime is 21530412227. The reversal of 21530412213 is 31221403512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21530412213 - 2² = 21530412209 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530412283) 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, 3588402033 + ... + 3588402038.

It is an arithmetic number, because the mean of its divisors is an integer number (7176804072).

Almost surely, 2^21530412213 is an apocalyptic number.

It is an amenable number.

21530412213 is a deficient number, since it is larger than the sum of its proper divisors (7176804075).

21530412213 is an equidigital number, since it uses as much as digits as its factorization.

21530412213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7176804074.

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 21530412213 its reverse (31221403512), we get a palindrome (52751815725).

The spelling of 21530412213 in words is "twenty-one billion, five hundred thirty million, four hundred twelve thousand, two hundred thirteen".