1321230231821 has 2 divisors, whose sum is σ = 1321230231822. Its totient is φ = 1321230231820.

The previous prime is 1321230231803. The next prime is 1321230231877. The reversal of 1321230231821 is 1281320321231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 715656781225 + 605573450596 = 845965^2 + 778186^2 .

It is a cyclic number.

It is not a de Polignac number, because 1321230231821 - 2³⁰ = 1320156489997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1321230231121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660615115910 + 660615115911.

It is an arithmetic number, because the mean of its divisors is an integer number (660615115911).

Almost surely, 2^{1321230231821} is an apocalyptic number.

It is an amenable number.

1321230231821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1321230231821 is an equidigital number, since it uses as much as digits as its factorization.

1321230231821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The spelling of 1321230231821 in words is "one trillion, three hundred twenty-one billion, two hundred thirty million, two hundred thirty-one thousand, eight hundred twenty-one".