12609821381 has 2 divisors, whose sum is σ = 12609821382. Its totient is φ = 12609821380.

The previous prime is 12609821353. The next prime is 12609821387. The reversal of 12609821381 is 18312890621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12430020100 + 179801281 = 111490^2 + 13409^2 .

It is a cyclic number.

It is not a de Polignac number, because 12609821381 - 2²² = 12605627077 is a prime.

It is a super-2 number, since 2×12609821381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12609821387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6304910690 + 6304910691.

It is an arithmetic number, because the mean of its divisors is an integer number (6304910691).

Almost surely, 2^12609821381 is an apocalyptic number.

It is an amenable number.

12609821381 is a deficient number, since it is larger than the sum of its proper divisors (1).

12609821381 is an equidigital number, since it uses as much as digits as its factorization.

12609821381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 41.

The spelling of 12609821381 in words is "twelve billion, six hundred nine million, eight hundred twenty-one thousand, three hundred eighty-one".