1640321 has 8 divisors (see below), whose sum is σ = 1725504. Its totient is φ = 1557360.

The previous prime is 1640311. The next prime is 1640323. The reversal of 1640321 is 1230461.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1640321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1640321.

It is not an unprimeable number, because it can be changed into a prime (1640323) 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, 1076 + ... + 2106.

It is an arithmetic number, because the mean of its divisors is an integer number (215688).

2^1640321 is an apocalyptic number.

It is an amenable number.

1640321 is a deficient number, since it is larger than the sum of its proper divisors (85183).

1640321 is a wasteful number, since it uses less digits than its factorization.

1640321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1111.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1640321 is about 1280.7501707983. The cubic root of 1640321 is about 117.9350643393.

Adding to 1640321 its reverse (1230461), we get a palindrome (2870782).

The spelling of 1640321 in words is "one million, six hundred forty thousand, three hundred twenty-one".