1665044521 has 8 divisors (see below), whose sum is σ = 1913422784. Its totient is φ = 1419294960.

The previous prime is 1665044509. The next prime is 1665044531. The reversal of 1665044521 is 1254405661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1665044521 - 2⁹ = 1665044009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1665044531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 655815 + ... + 658348.

It is an arithmetic number, because the mean of its divisors is an integer number (239177848).

Almost surely, 2^1665044521 is an apocalyptic number.

It is an amenable number.

1665044521 is a deficient number, since it is larger than the sum of its proper divisors (248378263).

1665044521 is a wasteful number, since it uses less digits than its factorization.

1665044521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1314351.

The product of its (nonzero) digits is 28800, while the sum is 34.

The square root of 1665044521 is about 40804.9570640627. The cubic root of 1665044521 is about 1185.2463233657.

The spelling of 1665044521 in words is "one billion, six hundred sixty-five million, forty-four thousand, five hundred twenty-one".