1398431261 has 2 divisors, whose sum is σ = 1398431262. Its totient is φ = 1398431260.

The previous prime is 1398431233. The next prime is 1398431263. The reversal of 1398431261 is 1621348931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1376855236 + 21576025 = 37106^2 + 4645^2 .

It is a cyclic number.

It is not a de Polignac number, because 1398431261 - 2⁶ = 1398431197 is a prime.

Together with 1398431263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1398431263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 699215630 + 699215631.

It is an arithmetic number, because the mean of its divisors is an integer number (699215631).

Almost surely, 2^1398431261 is an apocalyptic number.

It is an amenable number.

1398431261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1398431261 is an equidigital number, since it uses as much as digits as its factorization.

1398431261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 38.

The square root of 1398431261 is about 37395.6048353279. The cubic root of 1398431261 is about 1118.2709452091.

The spelling of 1398431261 in words is "one billion, three hundred ninety-eight million, four hundred thirty-one thousand, two hundred sixty-one".