1001621 has 2 divisors, whose sum is σ = 1001622. Its totient is φ = 1001620.

The previous prime is 1001593. The next prime is 1001629. The reversal of 1001621 is 1261001.

1001621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 579121 + 422500 = 761^2 + 650^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500810 + 500811.

It is an arithmetic number, because the mean of its divisors is an integer number (500811).

2^1001621 is an apocalyptic number.

It is an amenable number.

1001621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001621 is an equidigital number, since it uses as much as digits as its factorization.

1001621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12, while the sum is 11.

The square root of 1001621 is about 1000.8101718108. The cubic root of 1001621 is about 100.0540041636.

Adding to 1001621 its reverse (1261001), we get a palindrome (2262622).

The spelling of 1001621 in words is "one million, one thousand, six hundred twenty-one".