21707222021 has 8 divisors (see below), whose sum is σ = 22985935704. Its totient is φ = 20428710400.

The previous prime is 21707221993. The next prime is 21707222023. The reversal of 21707222021 is 12022270712.

It can be written as a sum of positive squares in 4 ways, for example, as 744525796 + 20962696225 = 27286^2 + 144785^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21707222021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21707222023) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 208721 + ... + 294921.

It is an arithmetic number, because the mean of its divisors is an integer number (2873241963).

Almost surely, 2^21707222021 is an apocalyptic number.

It is an amenable number.

21707222021 is a deficient number, since it is larger than the sum of its proper divisors (1278713683).

21707222021 is a wasteful number, since it uses less digits than its factorization.

21707222021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101031.

The product of its (nonzero) digits is 1568, while the sum is 26.

Adding to 21707222021 its reverse (12022270712), we get a palindrome (33729492733).

The spelling of 21707222021 in words is "twenty-one billion, seven hundred seven million, two hundred twenty-two thousand, twenty-one".