1666625465 has 4 divisors (see below), whose sum is σ = 1999950564. Its totient is φ = 1333300368.

The previous prime is 1666625461. The next prime is 1666625479. The reversal of 1666625465 is 5645266661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1004129344 + 662496121 = 31688^2 + 25739^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666625465 - 2² = 1666625461 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666625461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166662542 + ... + 166662551.

It is an arithmetic number, because the mean of its divisors is an integer number (499987641).

Almost surely, 2^1666625465 is an apocalyptic number.

It is an amenable number.

1666625465 is a deficient number, since it is larger than the sum of its proper divisors (333325099).

1666625465 is an equidigital number, since it uses as much as digits as its factorization.

1666625465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333325098.

The product of its digits is 1555200, while the sum is 47.

The square root of 1666625465 is about 40824.3244279682. The cubic root of 1666625465 is about 1185.6213314207.

The spelling of 1666625465 in words is "one billion, six hundred sixty-six million, six hundred twenty-five thousand, four hundred sixty-five".