1243213391 has 4 divisors (see below), whose sum is σ = 1420815312. Its totient is φ = 1065611472.

The previous prime is 1243213379. The next prime is 1243213393. The reversal of 1243213391 is 1933123421.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1243213391 - 2⁶ = 1243213327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243213393) 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 in 3 ways as a sum of consecutive naturals, for example, 88800950 + ... + 88800963.

It is an arithmetic number, because the mean of its divisors is an integer number (355203828).

Almost surely, 2^1243213391 is an apocalyptic number.

1243213391 is a deficient number, since it is larger than the sum of its proper divisors (177601921).

1243213391 is an equidigital number, since it uses as much as digits as its factorization.

1243213391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177601920.

The product of its digits is 3888, while the sum is 29.

The square root of 1243213391 is about 35259.2312877068. The cubic root of 1243213391 is about 1075.2642987425.

The spelling of 1243213391 in words is "one billion, two hundred forty-three million, two hundred thirteen thousand, three hundred ninety-one".