21784885351 has 4 divisors (see below), whose sum is σ = 22083308512. Its totient is φ = 21486462192.

The previous prime is 21784885349. The next prime is 21784885361. The reversal of 21784885351 is 15358848712.

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 21784885351 - 2¹ = 21784885349 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 (21784885301) 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, 149211471 + ... + 149211616.

It is an arithmetic number, because the mean of its divisors is an integer number (5520827128).

Almost surely, 2^21784885351 is an apocalyptic number.

21784885351 is a deficient number, since it is larger than the sum of its proper divisors (298423161).

21784885351 is an equidigital number, since it uses as much as digits as its factorization.

21784885351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298423160.

The product of its digits is 2150400, while the sum is 52.

The spelling of 21784885351 in words is "twenty-one billion, seven hundred eighty-four million, eight hundred eighty-five thousand, three hundred fifty-one".