65621531761 has 2 divisors, whose sum is σ = 65621531762. Its totient is φ = 65621531760.

The previous prime is 65621531753. The next prime is 65621531791. The reversal of 65621531761 is 16713512656.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53351760400 + 12269771361 = 230980^2 + 110769^2 .

It is a cyclic number.

It is not a de Polignac number, because 65621531761 - 2³ = 65621531753 is a prime.

It is a super-2 number, since 2×65621531761² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (65621531791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32810765880 + 32810765881.

It is an arithmetic number, because the mean of its divisors is an integer number (32810765881).

Almost surely, 2^65621531761 is an apocalyptic number.

It is an amenable number.

65621531761 is a deficient number, since it is larger than the sum of its proper divisors (1).

65621531761 is an equidigital number, since it uses as much as digits as its factorization.

65621531761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 43.

The spelling of 65621531761 in words is "sixty-five billion, six hundred twenty-one million, five hundred thirty-one thousand, seven hundred sixty-one".