65720533979561 has 4 divisors (see below), whose sum is σ = 65877384896400. Its totient is φ = 65563683062724.

The previous prime is 65720533979491. The next prime is 65720533979567. The reversal of 65720533979561 is 16597933502756.

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 not a de Polignac number, because 65720533979561 - 2¹⁰ = 65720533978537 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 65720533979491 and 65720533979500.

It is not an unprimeable number, because it can be changed into a prime (65720533979567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78425457791 + ... + 78425458628.

It is an arithmetic number, because the mean of its divisors is an integer number (16469346224100).

Almost surely, 2^{65720533979561} is an apocalyptic number.

It is an amenable number.

65720533979561 is a deficient number, since it is larger than the sum of its proper divisors (156850916839).

65720533979561 is a wasteful number, since it uses less digits than its factorization.

65720533979561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156850916838.

The product of its (nonzero) digits is 321489000, while the sum is 68.

The spelling of 65720533979561 in words is "sixty-five trillion, seven hundred twenty billion, five hundred thirty-three million, nine hundred seventy-nine thousand, five hundred sixty-one".