1491971329 has 2 divisors, whose sum is σ = 1491971330. Its totient is φ = 1491971328.

The previous prime is 1491971321. The next prime is 1491971353. The reversal of 1491971329 is 9231791941.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1355712400 + 136258929 = 36820^2 + 11673^2 .

It is an emirp because it is prime and its reverse (9231791941) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1491971329 - 2³ = 1491971321 is a prime.

It is not a weakly prime, because it can be changed into another prime (1491971321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 745985664 + 745985665.

It is an arithmetic number, because the mean of its divisors is an integer number (745985665).

Almost surely, 2^1491971329 is an apocalyptic number.

It is an amenable number.

1491971329 is a deficient number, since it is larger than the sum of its proper divisors (1).

1491971329 is an equidigital number, since it uses as much as digits as its factorization.

1491971329 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 46.

The square root of 1491971329 is about 38626.0446978460. The cubic root of 1491971329 is about 1142.6682469402.

The spelling of 1491971329 in words is "one billion, four hundred ninety-one million, nine hundred seventy-one thousand, three hundred twenty-nine".