19999631 has 2 divisors, whose sum is σ = 19999632. Its totient is φ = 19999630.

The previous prime is 19999583. The next prime is 19999663. The reversal of 19999631 is 13699991.

It is a strong prime.

It is an emirp because it is prime and its reverse (13699991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19999631 - 2¹⁰ = 19998607 is a prime.

It is a super-2 number, since 2×19999631² = 799970480272322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19999831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999815 + 9999816.

It is an arithmetic number, because the mean of its divisors is an integer number (9999816).

Almost surely, 2^19999631 is an apocalyptic number.

19999631 is a deficient number, since it is larger than the sum of its proper divisors (1).

19999631 is an equidigital number, since it uses as much as digits as its factorization.

19999631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 118098, while the sum is 47.

The square root of 19999631 is about 4472.0946993551. The cubic root of 19999631 is about 271.4400922824.

The spelling of 19999631 in words is "nineteen million, nine hundred ninety-nine thousand, six hundred thirty-one".