1620217 has 2 divisors, whose sum is σ = 1620218. Its totient is φ = 1620216.

The previous prime is 1620209. The next prime is 1620233. The reversal of 1620217 is 7120261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1279161 + 341056 = 1131^2 + 584^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620217 - 2³ = 1620209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1620194 and 1620203.

It is not a weakly prime, because it can be changed into another prime (1620247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810108 + 810109.

It is an arithmetic number, because the mean of its divisors is an integer number (810109).

2^1620217 is an apocalyptic number.

It is an amenable number.

1620217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620217 is an equidigital number, since it uses as much as digits as its factorization.

1620217 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 1620217 is about 1272.8774489321. The cubic root of 1620217 is about 117.4512729903.

Adding to 1620217 its reverse (7120261), we get a palindrome (8740478).

The spelling of 1620217 in words is "one million, six hundred twenty thousand, two hundred seventeen".