21784145503 has 4 divisors (see below), whose sum is σ = 22731282288. Its totient is φ = 20837008720.

The previous prime is 21784145447. The next prime is 21784145597. The reversal of 21784145503 is 30554148712.

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 21784145503 - 2¹³ = 21784137311 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 (21784145003) 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, 473568358 + ... + 473568403.

It is an arithmetic number, because the mean of its divisors is an integer number (5682820572).

Almost surely, 2^21784145503 is an apocalyptic number.

21784145503 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21784145503 is a deficient number, since it is larger than the sum of its proper divisors (947136785).

21784145503 is an equidigital number, since it uses as much as digits as its factorization.

21784145503 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 947136784.

The product of its (nonzero) digits is 134400, while the sum is 40.

The spelling of 21784145503 in words is "twenty-one billion, seven hundred eighty-four million, one hundred forty-five thousand, five hundred three".