65221411721 has 4 divisors (see below), whose sum is σ = 65734966272. Its totient is φ = 64707857172.

The previous prime is 65221411711. The next prime is 65221411741. The reversal of 65221411721 is 12711412256.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65221411721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65221411711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256777085 + ... + 256777338.

It is an arithmetic number, because the mean of its divisors is an integer number (16433741568).

Almost surely, 2^65221411721 is an apocalyptic number.

It is an amenable number.

65221411721 is a deficient number, since it is larger than the sum of its proper divisors (513554551).

65221411721 is a wasteful number, since it uses less digits than its factorization.

65221411721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513554550.

The product of its digits is 6720, while the sum is 32.

Adding to 65221411721 its reverse (12711412256), we get a palindrome (77932823977).

The spelling of 65221411721 in words is "sixty-five billion, two hundred twenty-one million, four hundred eleven thousand, seven hundred twenty-one".