1643497263 has 8 divisors (see below), whose sum is σ = 2434810800. Its totient is φ = 1095664824.

The previous prime is 1643497249. The next prime is 1643497291. The reversal of 1643497263 is 3627943461.

It is not a de Polignac number, because 1643497263 - 2⁸ = 1643497007 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643497463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30435108 + ... + 30435161.

It is an arithmetic number, because the mean of its divisors is an integer number (304351350).

Almost surely, 2^1643497263 is an apocalyptic number.

1643497263 is a deficient number, since it is larger than the sum of its proper divisors (791313537).

1643497263 is an equidigital number, since it uses as much as digits as its factorization.

1643497263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60870278 (or 60870272 counting only the distinct ones).

The product of its digits is 653184, while the sum is 45.

The square root of 1643497263 is about 40540.0698445378. The cubic root of 1643497263 is about 1180.1113710357. Note that the first 3 decimals are identical.

The spelling of 1643497263 in words is "one billion, six hundred forty-three million, four hundred ninety-seven thousand, two hundred sixty-three".