1538208491 has 2 divisors, whose sum is σ = 1538208492. Its totient is φ = 1538208490.

The previous prime is 1538208431. The next prime is 1538208557. The reversal of 1538208491 is 1948028351.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1538208491 - 2¹⁴ = 1538192107 is a prime.

It is not a weakly prime, because it can be changed into another prime (1538208431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 769104245 + 769104246.

It is an arithmetic number, because the mean of its divisors is an integer number (769104246).

Almost surely, 2^1538208491 is an apocalyptic number.

1538208491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1538208491 is an equidigital number, since it uses as much as digits as its factorization.

1538208491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 69120, while the sum is 41.

The square root of 1538208491 is about 39220.0011601224. The cubic root of 1538208491 is about 1154.3523767034.

The spelling of 1538208491 in words is "one billion, five hundred thirty-eight million, two hundred eight thousand, four hundred ninety-one".