1491798521 has 2 divisors, whose sum is σ = 1491798522. Its totient is φ = 1491798520.

The previous prime is 1491798499. The next prime is 1491798533. The reversal of 1491798521 is 1258971941.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1420159225 + 71639296 = 37685^2 + 8464^2 .

It is a cyclic number.

It is not a de Polignac number, because 1491798521 - 2¹⁸ = 1491536377 is a prime.

It is not a weakly prime, because it can be changed into another prime (1491795521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 745899260 + 745899261.

It is an arithmetic number, because the mean of its divisors is an integer number (745899261).

Almost surely, 2^1491798521 is an apocalyptic number.

It is an amenable number.

1491798521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1491798521 is an equidigital number, since it uses as much as digits as its factorization.

1491798521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 181440, while the sum is 47.

The square root of 1491798521 is about 38623.8076968079. The cubic root of 1491798521 is about 1142.6241286128.

The spelling of 1491798521 in words is "one billion, four hundred ninety-one million, seven hundred ninety-eight thousand, five hundred twenty-one".