1649621 has 2 divisors, whose sum is σ = 1649622. Its totient is φ = 1649620.

The previous prime is 1649611. The next prime is 1649639. The reversal of 1649621 is 1269461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1500625 + 148996 = 1225^2 + 386^2 .

It is an emirp because it is prime and its reverse (1269461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1649621 - 2¹⁴ = 1633237 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1649611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 824810 + 824811.

It is an arithmetic number, because the mean of its divisors is an integer number (824811).

2^1649621 is an apocalyptic number.

It is an amenable number.

1649621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1649621 is an equidigital number, since it uses as much as digits as its factorization.

1649621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 29.

The square root of 1649621 is about 1284.3757238441. The cubic root of 1649621 is about 118.1575268525.

The spelling of 1649621 in words is "one million, six hundred forty-nine thousand, six hundred twenty-one".