1664515 has 4 divisors (see below), whose sum is σ = 1997424. Its totient is φ = 1331608.

The previous prime is 1664501. The next prime is 1664543. The reversal of 1664515 is 5154661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5154661 = 2027 ⋅2543.

It is a cyclic number.

It is not a de Polignac number, because 1664515 - 2⁷ = 1664387 is a prime.

It is a super-2 number, since 2×1664515² = 5541220370450, which contains 22 as substring.

It is a Duffinian number.

1664515 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166447 + ... + 166456.

It is an arithmetic number, because the mean of its divisors is an integer number (499356).

2^1664515 is an apocalyptic number.

1664515 is a deficient number, since it is larger than the sum of its proper divisors (332909).

1664515 is an equidigital number, since it uses as much as digits as its factorization.

1664515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332908.

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

The square root of 1664515 is about 1290.1608426859. The cubic root of 1664515 is about 118.5120665192.

The spelling of 1664515 in words is "one million, six hundred sixty-four thousand, five hundred fifteen".