65211056721621 has 40 divisors (see below), whose sum is σ = 100559575209984. Its totient is φ = 42070336230240.

The previous prime is 65211056721611. The next prime is 65211056721661. The reversal of 65211056721621 is 12612765011256.

65211056721621 is a `hidden beast` number, since 6 + 5 + 2 + 1 + 1 + 0 + 567 + 21 + 62 + 1 = 666.

It is not a de Polignac number, because 65211056721621 - 2¹⁰ = 65211056720597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65211056721611) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 83511420 + ... + 84288666.

Almost surely, 2^{65211056721621} is an apocalyptic number.

It is an amenable number.

65211056721621 is a deficient number, since it is larger than the sum of its proper divisors (35348518488363).

65211056721621 is a wasteful number, since it uses less digits than its factorization.

65211056721621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 810703 (or 810694 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 45.

The spelling of 65211056721621 in words is "sixty-five trillion, two hundred eleven billion, fifty-six million, seven hundred twenty-one thousand, six hundred twenty-one".