12957821 has 2 divisors, whose sum is σ = 12957822. Its totient is φ = 12957820.

The previous prime is 12957797. The next prime is 12957839. The reversal of 12957821 is 12875921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10432900 + 2524921 = 3230^2 + 1589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12957821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12957851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6478910 + 6478911.

It is an arithmetic number, because the mean of its divisors is an integer number (6478911).

Almost surely, 2^12957821 is an apocalyptic number.

It is an amenable number.

12957821 is a deficient number, since it is larger than the sum of its proper divisors (1).

12957821 is an equidigital number, since it uses as much as digits as its factorization.

12957821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10080, while the sum is 35.

The square root of 12957821 is about 3599.6973483892. The cubic root of 12957821 is about 234.8788933857.

The spelling of 12957821 in words is "twelve million, nine hundred fifty-seven thousand, eight hundred twenty-one".