1640521 has 4 divisors (see below), whose sum is σ = 1711872. Its totient is φ = 1569172.

The previous prime is 1640519. The next prime is 1640531. The reversal of 1640521 is 1250461.

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.

It is a cyclic number.

It is not a de Polignac number, because 1640521 - 2¹ = 1640519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35641 + ... + 35686.

It is an arithmetic number, because the mean of its divisors is an integer number (427968).

2^1640521 is an apocalyptic number.

It is an amenable number.

1640521 is a deficient number, since it is larger than the sum of its proper divisors (71351).

1640521 is an equidigital number, since it uses as much as digits as its factorization.

1640521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71350.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 1640521 is about 1280.8282476585. The cubic root of 1640521 is about 117.9398573147.

Adding to 1640521 its reverse (1250461), we get a palindrome (2890982).

The spelling of 1640521 in words is "one million, six hundred forty thousand, five hundred twenty-one".