1664551 has 8 divisors (see below), whose sum is σ = 1910304. Its totient is φ = 1420800.

The previous prime is 1664549. The next prime is 1664557. The reversal of 1664551 is 1554661.

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 1664551 - 2¹ = 1664549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2511 + ... + 3103.

It is an arithmetic number, because the mean of its divisors is an integer number (238788).

2^1664551 is an apocalyptic number.

1664551 is a deficient number, since it is larger than the sum of its proper divisors (245753).

1664551 is an equidigital number, since it uses as much as digits as its factorization.

1664551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1001.

The product of its digits is 3600, while the sum is 28.

The square root of 1664551 is about 1290.1747943593. The cubic root of 1664551 is about 118.5129209029.

The spelling of 1664551 in words is "one million, six hundred sixty-four thousand, five hundred fifty-one".