1338721437809 has 32 divisors (see below), whose sum is σ = 1613811133440. Its totient is φ = 1086776151552.

The previous prime is 1338721437787. The next prime is 1338721437847. The reversal of 1338721437809 is 9087341278331.

It is a happy number.

It is not a de Polignac number, because 1338721437809 - 2²⁴ = 1338704660593 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1338721437409) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 747047 + ... + 1798755.

It is an arithmetic number, because the mean of its divisors is an integer number (50431597920).

Almost surely, 2^{1338721437809} is an apocalyptic number.

It is an amenable number.

1338721437809 is a deficient number, since it is larger than the sum of its proper divisors (275089695631).

1338721437809 is a wasteful number, since it uses less digits than its factorization.

1338721437809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051889.

The product of its (nonzero) digits is 6096384, while the sum is 56.

The spelling of 1338721437809 in words is "one trillion, three hundred thirty-eight billion, seven hundred twenty-one million, four hundred thirty-seven thousand, eight hundred nine".