1620321 has 8 divisors (see below), whose sum is σ = 2287584. Its totient is φ = 1016640.

The previous prime is 1620319. The next prime is 1620329. The reversal of 1620321 is 1230261.

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

It is not a de Polignac number, because 1620321 - 2¹ = 1620319 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1620321.

It is not an unprimeable number, because it can be changed into a prime (1620329) 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, 15835 + ... + 15936.

It is an arithmetic number, because the mean of its divisors is an integer number (285948).

2^1620321 is an apocalyptic number.

It is an amenable number.

1620321 is a deficient number, since it is larger than the sum of its proper divisors (667263).

1620321 is a wasteful number, since it uses less digits than its factorization.

1620321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31791.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 1620321 is about 1272.9183005991. The cubic root of 1620321 is about 117.4537859605.

Adding to 1620321 its reverse (1230261), we get a palindrome (2850582).

The spelling of 1620321 in words is "one million, six hundred twenty thousand, three hundred twenty-one".