66145160651661 has 144 divisors (see below), whose sum is σ = 124645671521280. Its totient is φ = 33465470008320.

The previous prime is 66145160651657. The next prime is 66145160651693. The reversal of 66145160651661 is 16615606154166.

66145160651661 is a `hidden beast` number, since 6 + 6 + 1 + 4 + 5 + 1 + 60 + 6 + 516 + 61 = 666.

It is not a de Polignac number, because 66145160651661 - 2² = 66145160651657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66145160651598 and 66145160651607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66145160651641) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 18435880 + ... + 21729518.

It is an arithmetic number, because the mean of its divisors is an integer number (865594941120).

Almost surely, 2^{66145160651661} is an apocalyptic number.

It is an amenable number.

66145160651661 is a deficient number, since it is larger than the sum of its proper divisors (58500510869619).

66145160651661 is a wasteful number, since it uses less digits than its factorization.

66145160651661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3293816 (or 3293806 counting only the distinct ones).

The product of its (nonzero) digits is 4665600, while the sum is 54.

The spelling of 66145160651661 in words is "sixty-six trillion, one hundred forty-five billion, one hundred sixty million, six hundred fifty-one thousand, six hundred sixty-one".