21313212169 has 2 divisors, whose sum is σ = 21313212170. Its totient is φ = 21313212168.

The previous prime is 21313212061. The next prime is 21313212191. The reversal of 21313212169 is 96121231312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13291322944 + 8021889225 = 115288^2 + 89565^2 .

It is a cyclic number.

It is not a de Polignac number, because 21313212169 - 2¹⁵ = 21313179401 is a prime.

It is a super-2 number, since 2×21313212169² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21313212169.

It is not a weakly prime, because it can be changed into another prime (21313212199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656606084 + 10656606085.

It is an arithmetic number, because the mean of its divisors is an integer number (10656606085).

Almost surely, 2^21313212169 is an apocalyptic number.

It is an amenable number.

21313212169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21313212169 is an equidigital number, since it uses as much as digits as its factorization.

21313212169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 31.

The spelling of 21313212169 in words is "twenty-one billion, three hundred thirteen million, two hundred twelve thousand, one hundred sixty-nine".