1243944861 has 4 divisors (see below), whose sum is σ = 1658593152. Its totient is φ = 829296572.

The previous prime is 1243944851. The next prime is 1243944899. The reversal of 1243944861 is 1684493421.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1243944861 - 2¹⁰ = 1243943837 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1243944851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207324141 + ... + 207324146.

It is an arithmetic number, because the mean of its divisors is an integer number (414648288).

Almost surely, 2^1243944861 is an apocalyptic number.

It is an amenable number.

1243944861 is a deficient number, since it is larger than the sum of its proper divisors (414648291).

1243944861 is an equidigital number, since it uses as much as digits as its factorization.

1243944861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414648290.

The product of its digits is 165888, while the sum is 42.

The square root of 1243944861 is about 35269.6025069748. The cubic root of 1243944861 is about 1075.4751419700.

The spelling of 1243944861 in words is "one billion, two hundred forty-three million, nine hundred forty-four thousand, eight hundred sixty-one".