72784321663 has 4 divisors (see below), whose sum is σ = 73602123120. Its totient is φ = 71966520208.

The previous prime is 72784321657. The next prime is 72784321693. The reversal of 72784321663 is 36612348727.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 72784321663 - 2⁹ = 72784321151 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 (72784321693) 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 3 ways as a sum of consecutive naturals, for example, 408900595 + ... + 408900772.

It is an arithmetic number, because the mean of its divisors is an integer number (18400530780).

Almost surely, 2^72784321663 is an apocalyptic number.

72784321663 is a deficient number, since it is larger than the sum of its proper divisors (817801457).

72784321663 is an equidigital number, since it uses as much as digits as its factorization.

72784321663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 817801456.

The product of its digits is 2032128, while the sum is 49.

The spelling of 72784321663 in words is "seventy-two billion, seven hundred eighty-four million, three hundred twenty-one thousand, six hundred sixty-three".