1643264520 has 64 divisors (see below), whose sum is σ = 4943358720. Its totient is φ = 436998144.

The previous prime is 1643264501. The next prime is 1643264527. The reversal of 1643264520 is 254623461.

It is not an unprimeable number, because it can be changed into a prime (1643264527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25384 + ... + 62696.

It is an arithmetic number, because the mean of its divisors is an integer number (77239980).

Almost surely, 2^1643264520 is an apocalyptic number.

1643264520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643264520 is an abundant number, since it is smaller than the sum of its proper divisors (3300094200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1643264520 is a wasteful number, since it uses less digits than its factorization.

1643264520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37694 (or 37690 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 1643264520 is about 40537.1992125751. The cubic root of 1643264520 is about 1180.0556614556.

Adding to 1643264520 its reverse (254623461), we get a palindrome (1897887981).

The spelling of 1643264520 in words is "one billion, six hundred forty-three million, two hundred sixty-four thousand, five hundred twenty".