208681631 has 2 divisors, whose sum is σ = 208681632. Its totient is φ = 208681630.

The previous prime is 208681609. The next prime is 208681637. The reversal of 208681631 is 136186802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 208681631 - 2¹⁸ = 208419487 is a prime.

It is a super-2 number, since 2×208681631² = 87096046233640322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 208681591 and 208681600.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208681637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104340815 + 104340816.

It is an arithmetic number, because the mean of its divisors is an integer number (104340816).

Almost surely, 2^208681631 is an apocalyptic number.

208681631 is a deficient number, since it is larger than the sum of its proper divisors (1).

208681631 is an equidigital number, since it uses as much as digits as its factorization.

208681631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 208681631 is about 14445.8170762335. The cubic root of 208681631 is about 593.1457288532.

The spelling of 208681631 in words is "two hundred eight million, six hundred eighty-one thousand, six hundred thirty-one".