665474989 has 2 divisors, whose sum is σ = 665474990. Its totient is φ = 665474988.

The previous prime is 665474963. The next prime is 665475017. The reversal of 665474989 is 989474566.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 573985764 + 91489225 = 23958^2 + 9565^2 .

It is a cyclic number.

It is not a de Polignac number, because 665474989 - 2¹⁵ = 665442221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665474189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332737494 + 332737495.

It is an arithmetic number, because the mean of its divisors is an integer number (332737495).

Almost surely, 2^665474989 is an apocalyptic number.

It is an amenable number.

665474989 is a deficient number, since it is larger than the sum of its proper divisors (1).

665474989 is an equidigital number, since it uses as much as digits as its factorization.

665474989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13063680, while the sum is 58.

The square root of 665474989 is about 25796.8019141908. The cubic root of 665474989 is about 873.0596411211.

The spelling of 665474989 in words is "six hundred sixty-five million, four hundred seventy-four thousand, nine hundred eighty-nine".