21654781712 has 10 divisors (see below), whose sum is σ = 41956139598. Its totient is φ = 10827390848.

The previous prime is 21654781693. The next prime is 21654781723. The reversal of 21654781712 is 21718745612.

It can be written as a sum of positive squares in only one way, i.e., 21649002496 + 5779216 = 147136^2 + 2404^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 676711913 + ... + 676711944.

Almost surely, 2^21654781712 is an apocalyptic number.

It is an amenable number.

21654781712 is a deficient number, since it is larger than the sum of its proper divisors (20301357886).

21654781712 is a wasteful number, since it uses less digits than its factorization.

21654781712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1353423865 (or 1353423859 counting only the distinct ones).

The product of its digits is 188160, while the sum is 44.

The spelling of 21654781712 in words is "twenty-one billion, six hundred fifty-four million, seven hundred eighty-one thousand, seven hundred twelve".