21221709568 has 36 divisors (see below), whose sum is σ = 42438243400. Its totient is φ = 10591386624.

The previous prime is 21221709541. The next prime is 21221709571. The reversal of 21221709568 is 86590712212.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64258 + ... + 215806.

Almost surely, 2^21221709568 is an apocalyptic number.

It is an amenable number.

21221709568 is a deficient number, since it is larger than the sum of its proper divisors (21216533832).

21221709568 is an equidigital number, since it uses as much as digits as its factorization.

21221709568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152112 (or 152098 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 43.

The spelling of 21221709568 in words is "twenty-one billion, two hundred twenty-one million, seven hundred nine thousand, five hundred sixty-eight".