1641666625 has 32 divisors (see below), whose sum is σ = 2191082400. Its totient is φ = 1223680000.

The previous prime is 1641666617. The next prime is 1641666647. The reversal of 1641666625 is 5266661461.

It can be written as a sum of positive squares in 16 ways, for example, as 918271809 + 723394816 = 30303^2 + 26896^2 .

It is not a de Polignac number, because 1641666625 - 2³ = 1641666617 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 210801 + ... + 218449.

It is an arithmetic number, because the mean of its divisors is an integer number (68471325).

Almost surely, 2^1641666625 is an apocalyptic number.

It is an amenable number.

1641666625 is a deficient number, since it is larger than the sum of its proper divisors (549415775).

1641666625 is a wasteful number, since it uses less digits than its factorization.

1641666625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7782 (or 7772 counting only the distinct ones).

The product of its digits is 311040, while the sum is 43.

The square root of 1641666625 is about 40517.4854229628. The cubic root of 1641666625 is about 1179.6730457273.

The spelling of 1641666625 in words is "one billion, six hundred forty-one million, six hundred sixty-six thousand, six hundred twenty-five".