1999631 has 2 divisors, whose sum is σ = 1999632. Its totient is φ = 1999630.

The previous prime is 1999619. The next prime is 1999633. The reversal of 1999631 is 1369991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1999631 - 2⁶ = 1999567 is a prime.

It is a super-2 number, since 2×1999631² = 7997048272322, which contains 22 as substring.

Together with 1999633, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999633) 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, 999815 + 999816.

It is an arithmetic number, because the mean of its divisors is an integer number (999816).

2^1999631 is an apocalyptic number.

1999631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999631 is an equidigital number, since it uses as much as digits as its factorization.

1999631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13122, while the sum is 38.

The square root of 1999631 is about 1414.0830951539. The cubic root of 1999631 is about 125.9843559984.

The spelling of 1999631 in words is "one million, nine hundred ninety-nine thousand, six hundred thirty-one".