665749757 has 2 divisors, whose sum is σ = 665749758. Its totient is φ = 665749756.

The previous prime is 665749751. The next prime is 665749793. The reversal of 665749757 is 757947566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 572453476 + 93296281 = 23926^2 + 9659^2 .

It is a cyclic number.

It is not a de Polignac number, because 665749757 - 2¹⁶ = 665684221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665749751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332874878 + 332874879.

It is an arithmetic number, because the mean of its divisors is an integer number (332874879).

Almost surely, 2^665749757 is an apocalyptic number.

It is an amenable number.

665749757 is a deficient number, since it is larger than the sum of its proper divisors (1).

665749757 is an equidigital number, since it uses as much as digits as its factorization.

665749757 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11113200, while the sum is 56.

The square root of 665749757 is about 25802.1269859676. The cubic root of 665749757 is about 873.1797837996.

The spelling of 665749757 in words is "six hundred sixty-five million, seven hundred forty-nine thousand, seven hundred fifty-seven".