1664537 has 4 divisors (see below), whose sum is σ = 1902336. Its totient is φ = 1426740.

The previous prime is 1664501. The next prime is 1664543. The reversal of 1664537 is 7354661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 7354661 = 29 ⋅253609.

It is not a de Polignac number, because 1664537 - 2¹⁰ = 1663513 is a prime.

It is a Duffinian number.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 118889 + ... + 118902.

It is an arithmetic number, because the mean of its divisors is an integer number (475584).

2^1664537 is an apocalyptic number.

It is an amenable number.

1664537 is a deficient number, since it is larger than the sum of its proper divisors (237799).

1664537 is an equidigital number, since it uses as much as digits as its factorization.

1664537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237798.

The product of its digits is 15120, while the sum is 32.

The square root of 1664537 is about 1290.1693687264. The cubic root of 1664537 is about 118.5125886440.

The spelling of 1664537 in words is "one million, six hundred sixty-four thousand, five hundred thirty-seven".