1205342403521 has 2 divisors, whose sum is σ = 1205342403522. Its totient is φ = 1205342403520.

The previous prime is 1205342403493. The next prime is 1205342403523. The reversal of 1205342403521 is 1253042435021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1072581279025 + 132761124496 = 1035655^2 + 364364^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1205342403521 is a prime.

Together with 1205342403523, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1205342403523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 602671201760 + 602671201761.

It is an arithmetic number, because the mean of its divisors is an integer number (602671201761).

Almost surely, 2^{1205342403521} is an apocalyptic number.

It is an amenable number.

1205342403521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1205342403521 is an equidigital number, since it uses as much as digits as its factorization.

1205342403521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28800, while the sum is 32.

Adding to 1205342403521 its reverse (1253042435021), we get a palindrome (2458384838542).

The spelling of 1205342403521 in words is "one trillion, two hundred five billion, three hundred forty-two million, four hundred three thousand, five hundred twenty-one".