21291656924 has 12 divisors (see below), whose sum is σ = 37278423000. Its totient is φ = 10640678928.

The previous prime is 21291656891. The next prime is 21291656941. The reversal of 21291656924 is 42965619212.

It is a congruent number.

It is an unprimeable number.

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, 1278074 + ... + 1294625.

It is an arithmetic number, because the mean of its divisors is an integer number (3106535250).

Almost surely, 2^21291656924 is an apocalyptic number.

It is an amenable number.

21291656924 is a deficient number, since it is larger than the sum of its proper divisors (15986766076).

21291656924 is a wasteful number, since it uses less digits than its factorization.

21291656924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2574772 (or 2574770 counting only the distinct ones).

The product of its digits is 466560, while the sum is 47.

The spelling of 21291656924 in words is "twenty-one billion, two hundred ninety-one million, six hundred fifty-six thousand, nine hundred twenty-four".