1630621 has 2 divisors, whose sum is σ = 1630622. Its totient is φ = 1630620.

The previous prime is 1630619. The next prime is 1630633. The reversal of 1630621 is 1260361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1562500 + 68121 = 1250^2 + 261^2 .

It is an emirp because it is prime and its reverse (1260361) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1630621 - 2¹ = 1630619 is a prime.

Together with 1630619, it forms a pair of twin primes.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1630021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 815310 + 815311.

It is an arithmetic number, because the mean of its divisors is an integer number (815311).

2^1630621 is an apocalyptic number.

It is an amenable number.

1630621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1630621 is an equidigital number, since it uses as much as digits as its factorization.

1630621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 1630621 is about 1276.9577126906. The cubic root of 1630621 is about 117.7021358438.

Adding to 1630621 its reverse (1260361), we get a palindrome (2890982).

The spelling of 1630621 in words is "one million, six hundred thirty thousand, six hundred twenty-one".