21819333651 has 4 divisors (see below), whose sum is σ = 29092444872. Its totient is φ = 14546222432.

The previous prime is 21819333649. The next prime is 21819333661. The reversal of 21819333651 is 15633391812.

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 21819333651 - 2¹ = 21819333649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21819333611) 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 3 ways as a sum of consecutive naturals, for example, 3636555606 + ... + 3636555611.

It is an arithmetic number, because the mean of its divisors is an integer number (7273111218).

Almost surely, 2^21819333651 is an apocalyptic number.

21819333651 is a deficient number, since it is larger than the sum of its proper divisors (7273111221).

21819333651 is an equidigital number, since it uses as much as digits as its factorization.

21819333651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7273111220.

The product of its digits is 116640, while the sum is 42.

The spelling of 21819333651 in words is "twenty-one billion, eight hundred nineteen million, three hundred thirty-three thousand, six hundred fifty-one".