1665678432601 has 2 divisors, whose sum is σ = 1665678432602. Its totient is φ = 1665678432600.

The previous prime is 1665678432577. The next prime is 1665678432611. The reversal of 1665678432601 is 1062348765661.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1656307224576 + 9371208025 = 1286976^2 + 96805^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665678432601 - 2¹⁹ = 1665677908313 is a prime.

It is a pancake number, because a pancake can be divided into 1665678432601 parts by 1825200 straight cuts.

It is not a weakly prime, because it can be changed into another prime (1665678432611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832839216300 + 832839216301.

It is an arithmetic number, because the mean of its divisors is an integer number (832839216301).

Almost surely, 2^{1665678432601} is an apocalyptic number.

It is an amenable number.

1665678432601 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665678432601 is an equidigital number, since it uses as much as digits as its factorization.

1665678432601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8709120, while the sum is 55.

The spelling of 1665678432601 in words is "one trillion, six hundred sixty-five billion, six hundred seventy-eight million, four hundred thirty-two thousand, six hundred one".