1665427309 has 16 divisors (see below), whose sum is σ = 2138879232. Its totient is φ = 1260407808.

The previous prime is 1665427303. The next prime is 1665427391. The reversal of 1665427309 is 9037245661.

It is a cyclic number.

It is not a de Polignac number, because 1665427309 - 2⁹ = 1665426797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665427303) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 395764 + ... + 399949.

It is an arithmetic number, because the mean of its divisors is an integer number (133679952).

Almost surely, 2^1665427309 is an apocalyptic number.

It is an amenable number.

1665427309 is a deficient number, since it is larger than the sum of its proper divisors (473451923).

1665427309 is a wasteful number, since it uses less digits than its factorization.

1665427309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795756.

The product of its (nonzero) digits is 272160, while the sum is 43.

The square root of 1665427309 is about 40809.6472540501. The cubic root of 1665427309 is about 1185.3371444220.

The spelling of 1665427309 in words is "one billion, six hundred sixty-five million, four hundred twenty-seven thousand, three hundred nine".