1665663125 has 60 divisors (see below), whose sum is σ = 2445051708. Its totient is φ = 1130976000.

The previous prime is 1665663113. The next prime is 1665663137. The reversal of 1665663125 is 5213665661.

It is an interprime number because it is at equal distance from previous prime (1665663113) and next prime (1665663137).

It can be written as a sum of positive squares in 10 ways, for example, as 1083792241 + 581870884 = 32921^2 + 24122^2 .

It is not a de Polignac number, because 1665663125 - 2¹⁸ = 1665400981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 4195427 + ... + 4195823.

Almost surely, 2^1665663125 is an apocalyptic number.

It is an amenable number.

1665663125 is a deficient number, since it is larger than the sum of its proper divisors (779388583).

1665663125 is an equidigital number, since it uses as much as digits as its factorization.

1665663125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568 (or 546 counting only the distinct ones).

The product of its digits is 194400, while the sum is 41.

The square root of 1665663125 is about 40812.5363705810. The cubic root of 1665663125 is about 1185.3930876766.

The spelling of 1665663125 in words is "one billion, six hundred sixty-five million, six hundred sixty-three thousand, one hundred twenty-five".