1605631 has 2 divisors, whose sum is σ = 1605632. Its totient is φ = 1605630.

The previous prime is 1605629. The next prime is 1605677. The reversal of 1605631 is 1365061.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1605631 - 2¹ = 1605629 is a prime.

It is a super-2 number, since 2×1605631² = 5156101816322, which contains 22 as substring.

Together with 1605629, it forms a pair of twin primes.

It is a zygodrome in base 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1605691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802815 + 802816.

It is an arithmetic number, because the mean of its divisors is an integer number (802816).

2^1605631 is an apocalyptic number.

1605631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605631 is an equidigital number, since it uses as much as digits as its factorization.

1605631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 1605631 is about 1267.1349572954. The cubic root of 1605631 is about 117.0977584109.

The spelling of 1605631 in words is "one million, six hundred five thousand, six hundred thirty-one".