1521643 has 2 divisors, whose sum is σ = 1521644. Its totient is φ = 1521642.

The previous prime is 1521629. The next prime is 1521649. The reversal of 1521643 is 3461251.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1521643 is a prime.

1521643 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1521649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 760821 + 760822.

It is an arithmetic number, because the mean of its divisors is an integer number (760822).

2^1521643 is an apocalyptic number.

1521643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1521643 is an equidigital number, since it uses as much as digits as its factorization.

1521643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 22.

The square root of 1521643 is about 1233.5489451173. The cubic root of 1521643 is about 115.0193540205.

Adding to 1521643 its reverse (3461251), we get a palindrome (4982894).

The spelling of 1521643 in words is "one million, five hundred twenty-one thousand, six hundred forty-three".