21447309601 has 3 divisors (see below), whose sum is σ = 21447456051. Its totient is φ = 21447163152.

The previous prime is 21447309581. The next prime is 21447309647. The reversal of 21447309601 is 10690374412.

The square root of 21447309601 is 146449.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 15475111201 + 5972198400 = 124399^2 + 77280^2 .

It is not a de Polignac number, because 21447309601 - 2⁷ = 21447309473 is a prime.

It is a super-2 number, since 2×21447309601² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21447309671) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 73225 + ... + 219673.

It is an arithmetic number, because the mean of its divisors is an integer number (7149152017).

Almost surely, 2^21447309601 is an apocalyptic number.

21447309601 is the 146449-th square number.

21447309601 is the 73225-th centered octagonal number.

It is an amenable number.

21447309601 is a deficient number, since it is larger than the sum of its proper divisors (146450).

21447309601 is an frugal number, since it uses more digits than its factorization.

21447309601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292898 (or 146449 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 37.

The spelling of 21447309601 in words is "twenty-one billion, four hundred forty-seven million, three hundred nine thousand, six hundred one".