1397638409 has 2 divisors, whose sum is σ = 1397638410. Its totient is φ = 1397638408.

The previous prime is 1397638399. The next prime is 1397638453. The reversal of 1397638409 is 9048367931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1247502400 + 150136009 = 35320^2 + 12253^2 .

It is a cyclic number.

It is not a de Polignac number, because 1397638409 - 2¹² = 1397634313 is a prime.

It is not a weakly prime, because it can be changed into another prime (1397638009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 698819204 + 698819205.

It is an arithmetic number, because the mean of its divisors is an integer number (698819205).

Almost surely, 2^1397638409 is an apocalyptic number.

It is an amenable number.

1397638409 is a deficient number, since it is larger than the sum of its proper divisors (1).

1397638409 is an equidigital number, since it uses as much as digits as its factorization.

1397638409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 979776, while the sum is 50.

The square root of 1397638409 is about 37385.0024608800. The cubic root of 1397638409 is about 1118.0595676481.

The spelling of 1397638409 in words is "one billion, three hundred ninety-seven million, six hundred thirty-eight thousand, four hundred nine".