1244666891 has 8 divisors (see below), whose sum is σ = 1363130160. Its totient is φ = 1129449312.

The previous prime is 1244666887. The next prime is 1244666903. The reversal of 1244666891 is 1986664421.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1244666891 - 2² = 1244666887 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1244666851) 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 7 ways as a sum of consecutive naturals, for example, 810620 + ... + 812153.

It is an arithmetic number, because the mean of its divisors is an integer number (170391270).

Almost surely, 2^1244666891 is an apocalyptic number.

1244666891 is a deficient number, since it is larger than the sum of its proper divisors (118463269).

1244666891 is a wasteful number, since it uses less digits than its factorization.

1244666891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1622845.

The product of its digits is 497664, while the sum is 47.

The square root of 1244666891 is about 35279.8368902125. The cubic root of 1244666891 is about 1075.6831831108.

The spelling of 1244666891 in words is "one billion, two hundred forty-four million, six hundred sixty-six thousand, eight hundred ninety-one".