1665324761 has 2 divisors, whose sum is σ = 1665324762. Its totient is φ = 1665324760.

The previous prime is 1665324751. The next prime is 1665324767. The reversal of 1665324761 is 1674235661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1424609536 + 240715225 = 37744^2 + 15515^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665324761 - 2¹⁸ = 1665062617 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1665324767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832662380 + 832662381.

It is an arithmetic number, because the mean of its divisors is an integer number (832662381).

Almost surely, 2^1665324761 is an apocalyptic number.

It is an amenable number.

1665324761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665324761 is an equidigital number, since it uses as much as digits as its factorization.

1665324761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 41.

The square root of 1665324761 is about 40808.3908161055. The cubic root of 1665324761 is about 1185.3128150406.

It can be divided in two parts, 16653 and 24761, that added together give a palindrome (41414).

The spelling of 1665324761 in words is "one billion, six hundred sixty-five million, three hundred twenty-four thousand, seven hundred sixty-one".