1243940387 has 4 divisors (see below), whose sum is σ = 1245762360. Its totient is φ = 1242118416.

The previous prime is 1243940381. The next prime is 1243940389. The reversal of 1243940387 is 7830493421.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7830493421 = 47 ⋅166606243.

It is a cyclic number.

It is not a de Polignac number, because 1243940387 - 2⁶ = 1243940323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1243940381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 909962 + ... + 911327.

It is an arithmetic number, because the mean of its divisors is an integer number (311440590).

Almost surely, 2^1243940387 is an apocalyptic number.

1243940387 is a deficient number, since it is larger than the sum of its proper divisors (1821973).

1243940387 is an equidigital number, since it uses as much as digits as its factorization.

1243940387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1821972.

The product of its (nonzero) digits is 145152, while the sum is 41.

The square root of 1243940387 is about 35269.5390811958. The cubic root of 1243940387 is about 1075.4738526091.

The spelling of 1243940387 in words is "one billion, two hundred forty-three million, nine hundred forty thousand, three hundred eighty-seven".