20466449721 has 27 divisors (see below), whose sum is σ = 30293457519. Its totient is φ = 13314973392.

The previous prime is 20466449713. The next prime is 20466449777. The reversal of 20466449721 is 12794466402.

The square root of 20466449721 is 143061.

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

It can be written as a sum of positive squares in only one way, i.e., 330839721 + 20135610000 = 18189^2 + 141900^2 .

It is not a de Polignac number, because 20466449721 - 2³ = 20466449713 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20466449921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 18454315 + ... + 18455423.

Almost surely, 2^20466449721 is an apocalyptic number.

20466449721 is the 143061-st square number.

20466449721 is the 71531-st centered octagonal number.

It is an amenable number.

20466449721 is a deficient number, since it is larger than the sum of its proper divisors (9827007798).

20466449721 is an frugal number, since it uses more digits than its factorization.

20466449721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2310 (or 1155 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 45.

The spelling of 20466449721 in words is "twenty billion, four hundred sixty-six million, four hundred forty-nine thousand, seven hundred twenty-one".