21313212113 has 4 divisors (see below), whose sum is σ = 21313582500. Its totient is φ = 21312841728.

The previous prime is 21313212061. The next prime is 21313212169. The reversal of 21313212113 is 31121231312.

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 14039169169 + 7274042944 = 118487^2 + 85288^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313212113 - 2⁶ = 21313212049 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21313212013) 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, 78320 + ... + 220817.

It is an arithmetic number, because the mean of its divisors is an integer number (5328395625).

Almost surely, 2^21313212113 is an apocalyptic number.

It is an amenable number.

21313212113 is a deficient number, since it is larger than the sum of its proper divisors (370387).

21313212113 is an equidigital number, since it uses as much as digits as its factorization.

21313212113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370386.

The product of its digits is 216, while the sum is 20.

Adding to 21313212113 its reverse (31121231312), we get a palindrome (52434443425).

The spelling of 21313212113 in words is "twenty-one billion, three hundred thirteen million, two hundred twelve thousand, one hundred thirteen".