1643630479 has 4 divisors (see below), whose sum is σ = 1643711976. Its totient is φ = 1643548984.

The previous prime is 1643630441. The next prime is 1643630489. The reversal of 1643630479 is 9740363461.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1643630479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643630489) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14232 + ... + 59074.

It is an arithmetic number, because the mean of its divisors is an integer number (410927994).

Almost surely, 2^1643630479 is an apocalyptic number.

1643630479 is a deficient number, since it is larger than the sum of its proper divisors (81497).

1643630479 is an equidigital number, since it uses as much as digits as its factorization.

1643630479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81496.

The product of its (nonzero) digits is 326592, while the sum is 43.

The square root of 1643630479 is about 40541.7128276544. The cubic root of 1643630479 is about 1180.1432553741.

The spelling of 1643630479 in words is "one billion, six hundred forty-three million, six hundred thirty thousand, four hundred seventy-nine".