665748202421 has 2 divisors, whose sum is σ = 665748202422. Its totient is φ = 665748202420.

The previous prime is 665748202393. The next prime is 665748202423. The reversal of 665748202421 is 124202847566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 665715655396 + 32547025 = 815914^2 + 5705^2 .

It is a cyclic number.

It is not a de Polignac number, because 665748202421 - 2¹⁰ = 665748201397 is a prime.

It is a super-2 number, since 2×665748202421² (a number of 24 digits) contains 22 as substring.

Together with 665748202423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665748202423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332874101210 + 332874101211.

It is an arithmetic number, because the mean of its divisors is an integer number (332874101211).

Almost surely, 2^665748202421 is an apocalyptic number.

It is an amenable number.

665748202421 is a deficient number, since it is larger than the sum of its proper divisors (1).

665748202421 is an equidigital number, since it uses as much as digits as its factorization.

665748202421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1290240, while the sum is 47.

The spelling of 665748202421 in words is "six hundred sixty-five billion, seven hundred forty-eight million, two hundred two thousand, four hundred twenty-one".