1381780321 has 2 divisors, whose sum is σ = 1381780322. Its totient is φ = 1381780320.

The previous prime is 1381780303. The next prime is 1381780327. The reversal of 1381780321 is 1230871831.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 967210000 + 414570321 = 31100^2 + 20361^2 .

It is a cyclic number.

It is not a de Polignac number, because 1381780321 - 2¹⁹ = 1381256033 is a prime.

It is not a weakly prime, because it can be changed into another prime (1381780327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 690890160 + 690890161.

It is an arithmetic number, because the mean of its divisors is an integer number (690890161).

Almost surely, 2^1381780321 is an apocalyptic number.

It is an amenable number.

1381780321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1381780321 is an equidigital number, since it uses as much as digits as its factorization.

1381780321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 1381780321 is about 37172.3058337790. The cubic root of 1381780321 is about 1113.8148429251.

The spelling of 1381780321 in words is "one billion, three hundred eighty-one million, seven hundred eighty thousand, three hundred twenty-one".