21648642874 has 4 divisors (see below), whose sum is σ = 32472964314. Its totient is φ = 10824321436.

The previous prime is 21648642863. The next prime is 21648642923. The reversal of 21648642874 is 47824684612.

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

It can be written as a sum of positive squares in only one way, i.e., 21203728225 + 444914649 = 145615^2 + 21093^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5412160717 + ... + 5412160720.

Almost surely, 2^21648642874 is an apocalyptic number.

21648642874 is a deficient number, since it is larger than the sum of its proper divisors (10824321440).

21648642874 is a wasteful number, since it uses less digits than its factorization.

21648642874 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10824321439.

The product of its digits is 4128768, while the sum is 52.

The spelling of 21648642874 in words is "twenty-one billion, six hundred forty-eight million, six hundred forty-two thousand, eight hundred seventy-four".