65340721081 has 4 divisors (see below), whose sum is σ = 66315955792. Its totient is φ = 64365486372.

The previous prime is 65340721013. The next prime is 65340721141. The reversal of 65340721081 is 18012704356.

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 65340721081 - 2¹¹ = 65340719033 is a prime.

It is a super-2 number, since 2×65340721081² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 65340721081.

It is not an unprimeable number, because it can be changed into a prime (65340728081) 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, 487617255 + ... + 487617388.

It is an arithmetic number, because the mean of its divisors is an integer number (16578988948).

Almost surely, 2^65340721081 is an apocalyptic number.

It is an amenable number.

65340721081 is a deficient number, since it is larger than the sum of its proper divisors (975234711).

65340721081 is an equidigital number, since it uses as much as digits as its factorization.

65340721081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 975234710.

The product of its (nonzero) digits is 40320, while the sum is 37.

The spelling of 65340721081 in words is "sixty-five billion, three hundred forty million, seven hundred twenty-one thousand, eighty-one".