21722209721 has 8 divisors (see below), whose sum is σ = 21830878080. Its totient is φ = 21613748688.

The previous prime is 21722209711. The next prime is 21722209727. The reversal of 21722209721 is 12790222712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21722209721 - 2⁶ = 21722209657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21722209727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 160400 + ... + 263006.

It is an arithmetic number, because the mean of its divisors is an integer number (2728859760).

Almost surely, 2^21722209721 is an apocalyptic number.

It is an amenable number.

21722209721 is a deficient number, since it is larger than the sum of its proper divisors (108668359).

21722209721 is a wasteful number, since it uses less digits than its factorization.

21722209721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103663.

The product of its (nonzero) digits is 14112, while the sum is 35.

The spelling of 21722209721 in words is "twenty-one billion, seven hundred twenty-two million, two hundred nine thousand, seven hundred twenty-one".