1633561 has 2 divisors, whose sum is σ = 1633562. Its totient is φ = 1633560.

The previous prime is 1633559. The next prime is 1633573. The reversal of 1633561 is 1653361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1488400 + 145161 = 1220^2 + 381^2 .

It is a cyclic number.

It is not a de Polignac number, because 1633561 - 2¹ = 1633559 is a prime.

Together with 1633559, it forms a pair of twin primes.

1633561 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1633531) 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, 816780 + 816781.

It is an arithmetic number, because the mean of its divisors is an integer number (816781).

2^1633561 is an apocalyptic number.

It is an amenable number.

1633561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1633561 is an equidigital number, since it uses as much as digits as its factorization.

1633561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1620, while the sum is 25.

The square root of 1633561 is about 1278.1083678624. The cubic root of 1633561 is about 117.7728321236.

The spelling of 1633561 in words is "one million, six hundred thirty-three thousand, five hundred sixty-one".