1641445665 has 32 divisors (see below), whose sum is σ = 2699368320. Its totient is φ = 851268096.

The previous prime is 1641445649. The next prime is 1641445679. The reversal of 1641445665 is 5665441461.

It is a happy number.

It is not a de Polignac number, because 1641445665 - 2⁴ = 1641445649 is a prime.

It is a super-2 number, since 2×1641445665² = 5388687742294584450, which contains 22 as substring.

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, 142149 + ... + 153261.

It is an arithmetic number, because the mean of its divisors is an integer number (84355260).

Almost surely, 2^1641445665 is an apocalyptic number.

1641445665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1641445665 is a deficient number, since it is larger than the sum of its proper divisors (1057922655).

1641445665 is a wasteful number, since it uses less digits than its factorization.

1641445665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11393.

The product of its digits is 345600, while the sum is 42.

The square root of 1641445665 is about 40514.7586072039. The cubic root of 1641445665 is about 1179.6201173500.

The spelling of 1641445665 in words is "one billion, six hundred forty-one million, four hundred forty-five thousand, six hundred sixty-five".