1663323491 has 2 divisors, whose sum is σ = 1663323492. Its totient is φ = 1663323490.

The previous prime is 1663323481. The next prime is 1663323509. The reversal of 1663323491 is 1943233661.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1663323491 is a prime.

It is not a weakly prime, because it can be changed into another prime (1663323421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 831661745 + 831661746.

It is an arithmetic number, because the mean of its divisors is an integer number (831661746).

Almost surely, 2^1663323491 is an apocalyptic number.

1663323491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1663323491 is an equidigital number, since it uses as much as digits as its factorization.

1663323491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 38.

The square root of 1663323491 is about 40783.8631201116. The cubic root of 1663323491 is about 1184.8378162320.

The spelling of 1663323491 in words is "one billion, six hundred sixty-three million, three hundred twenty-three thousand, four hundred ninety-one".