21924748987 has 4 divisors (see below), whose sum is σ = 22391233056. Its totient is φ = 21458264920.

The previous prime is 21924748961. The next prime is 21924748991. The reversal of 21924748987 is 78984742912.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21924748987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21924748927) 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, 233241964 + ... + 233242057.

It is an arithmetic number, because the mean of its divisors is an integer number (5597808264).

Almost surely, 2^21924748987 is an apocalyptic number.

21924748987 is a deficient number, since it is larger than the sum of its proper divisors (466484069).

21924748987 is an equidigital number, since it uses as much as digits as its factorization.

21924748987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466484068.

The product of its digits is 16257024, while the sum is 61.

The spelling of 21924748987 in words is "twenty-one billion, nine hundred twenty-four million, seven hundred forty-eight thousand, nine hundred eighty-seven".