65657251661 has 2 divisors, whose sum is σ = 65657251662. Its totient is φ = 65657251660.

The previous prime is 65657251643. The next prime is 65657251679. The reversal of 65657251661 is 16615275656.

It is a balanced prime because it is at equal distance from previous prime (65657251643) and next prime (65657251679).

It can be written as a sum of positive squares in only one way, i.e., 47295375625 + 18361876036 = 217475^2 + 135506^2 .

It is a cyclic number.

It is not a de Polignac number, because 65657251661 - 2²² = 65653057357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65657253661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32828625830 + 32828625831.

It is an arithmetic number, because the mean of its divisors is an integer number (32828625831).

Almost surely, 2^65657251661 is an apocalyptic number.

It is an amenable number.

65657251661 is a deficient number, since it is larger than the sum of its proper divisors (1).

65657251661 is an equidigital number, since it uses as much as digits as its factorization.

65657251661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268000, while the sum is 50.

The spelling of 65657251661 in words is "sixty-five billion, six hundred fifty-seven million, two hundred fifty-one thousand, six hundred sixty-one".