21720561314 has 4 divisors (see below), whose sum is σ = 32580841974. Its totient is φ = 10860280656.

The previous prime is 21720561311. The next prime is 21720561337. The reversal of 21720561314 is 41316502712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 17349368089 + 4371193225 = 131717^2 + 66115^2 .

It is not an unprimeable number, because it can be changed into a prime (21720561311) 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 as a sum of consecutive naturals, namely, 5430140327 + ... + 5430140330.

Almost surely, 2^21720561314 is an apocalyptic number.

21720561314 is a deficient number, since it is larger than the sum of its proper divisors (10860280660).

21720561314 is a wasteful number, since it uses less digits than its factorization.

21720561314 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10860280659.

The product of its (nonzero) digits is 10080, while the sum is 32.

The spelling of 21720561314 in words is "twenty-one billion, seven hundred twenty million, five hundred sixty-one thousand, three hundred fourteen".