1338247781 has 4 divisors (see below), whose sum is σ = 1441189932. Its totient is φ = 1235305632.

The previous prime is 1338247777. The next prime is 1338247861. The reversal of 1338247781 is 1877428331.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 628504900 + 709742881 = 25070^2 + 26641^2 .

It is a cyclic number.

It is not a de Polignac number, because 1338247781 - 2² = 1338247777 is a prime.

It is a super-2 number, since 2×1338247781² = 3581814246702847922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1338247741) 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, 51471056 + ... + 51471081.

It is an arithmetic number, because the mean of its divisors is an integer number (360297483).

Almost surely, 2^1338247781 is an apocalyptic number.

It is an amenable number.

1338247781 is a deficient number, since it is larger than the sum of its proper divisors (102942151).

1338247781 is a wasteful number, since it uses less digits than its factorization.

1338247781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102942150.

The product of its digits is 225792, while the sum is 44.

The square root of 1338247781 is about 36582.0691186270. The cubic root of 1338247781 is about 1101.9930206749.

The spelling of 1338247781 in words is "one billion, three hundred thirty-eight million, two hundred forty-seven thousand, seven hundred eighty-one".