21984742551 has 8 divisors (see below), whose sum is σ = 29424447360. Its totient is φ = 14600766392.

The previous prime is 21984742541. The next prime is 21984742583. The reversal of 21984742551 is 15524748912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21984742551 - 2¹⁵ = 21984709783 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21984742551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21984742541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13931241 + ... + 13932818.

It is an arithmetic number, because the mean of its divisors is an integer number (3678055920).

Almost surely, 2^21984742551 is an apocalyptic number.

21984742551 is a deficient number, since it is larger than the sum of its proper divisors (7439704809).

21984742551 is a wasteful number, since it uses less digits than its factorization.

21984742551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27864325.

The product of its digits is 806400, while the sum is 48.

The spelling of 21984742551 in words is "twenty-one billion, nine hundred eighty-four million, seven hundred forty-two thousand, five hundred fifty-one".