665433021637 has 2 divisors, whose sum is σ = 665433021638. Its totient is φ = 665433021636.

The previous prime is 665433021629. The next prime is 665433021683. The reversal of 665433021637 is 736120334566.

It is a happy number.

It is an a-pointer prime, because the next prime (665433021683) can be obtained adding 665433021637 to its sum of digits (46).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 470992591521 + 194440430116 = 686289^2 + 440954^2 .

It is a cyclic number.

It is not a de Polignac number, because 665433021637 - 2³ = 665433021629 is a prime.

It is a super-2 number, since 2×665433021637² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665433021037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332716510818 + 332716510819.

It is an arithmetic number, because the mean of its divisors is an integer number (332716510819).

Almost surely, 2^665433021637 is an apocalyptic number.

It is an amenable number.

665433021637 is a deficient number, since it is larger than the sum of its proper divisors (1).

665433021637 is an equidigital number, since it uses as much as digits as its factorization.

665433021637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1632960, while the sum is 46.

The spelling of 665433021637 in words is "six hundred sixty-five billion, four hundred thirty-three million, twenty-one thousand, six hundred thirty-seven".