208400831 has 2 divisors, whose sum is σ = 208400832. Its totient is φ = 208400830.

The previous prime is 208400809. The next prime is 208400837. The reversal of 208400831 is 138004802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 208400831 - 2¹⁸ = 208138687 is a prime.

It is a super-2 number, since 2×208400831² = 86861812722981122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 208400831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208400837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104200415 + 104200416.

It is an arithmetic number, because the mean of its divisors is an integer number (104200416).

Almost surely, 2^208400831 is an apocalyptic number.

208400831 is a deficient number, since it is larger than the sum of its proper divisors (1).

208400831 is an equidigital number, since it uses as much as digits as its factorization.

208400831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 208400831 is about 14436.0947281458. The cubic root of 208400831 is about 592.8795657018.

The spelling of 208400831 in words is "two hundred eight million, four hundred thousand, eight hundred thirty-one".