1243949581905 has 32 divisors (see below), whose sum is σ = 2039791420800. Its totient is φ = 646963806720.

The previous prime is 1243949581879. The next prime is 1243949581943. The reversal of 1243949581905 is 5091859493421.

It is a happy number.

It is not a de Polignac number, because 1243949581905 - 2⁵ = 1243949581873 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 895771 + ... + 1813919.

It is an arithmetic number, because the mean of its divisors is an integer number (63743481900).

Almost surely, 2^{1243949581905} is an apocalyptic number.

1243949581905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1243949581905 is a deficient number, since it is larger than the sum of its proper divisors (795841838895).

1243949581905 is a wasteful number, since it uses less digits than its factorization.

1243949581905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 920401.

The product of its (nonzero) digits is 13996800, while the sum is 60.

The spelling of 1243949581905 in words is "one trillion, two hundred forty-three billion, nine hundred forty-nine million, five hundred eighty-one thousand, nine hundred five".