1620021 has 8 divisors (see below), whose sum is σ = 2326240. Its totient is φ = 996912.

The previous prime is 1620019. The next prime is 1620041. The reversal of 1620021 is 1200261.

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

It is not a de Polignac number, because 1620021 - 2¹ = 1620019 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1619979 and 1620006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620001) 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, 20731 + ... + 20808.

It is an arithmetic number, because the mean of its divisors is an integer number (290780).

2^1620021 is an apocalyptic number.

It is an amenable number.

1620021 is a deficient number, since it is larger than the sum of its proper divisors (706219).

1620021 is a wasteful number, since it uses less digits than its factorization.

1620021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41555.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1620021 is about 1272.8004556882. The cubic root of 1620021 is about 117.4465367157.

Adding to 1620021 its reverse (1200261), we get a palindrome (2820282).

The spelling of 1620021 in words is "one million, six hundred twenty thousand, twenty-one".