208139497 has 2 divisors, whose sum is σ = 208139498. Its totient is φ = 208139496.

The previous prime is 208139431. The next prime is 208139501. The reversal of 208139497 is 794931802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 191850201 + 16289296 = 13851^2 + 4036^2 .

It is a cyclic number.

It is not a de Polignac number, because 208139497 - 2¹⁵ = 208106729 is a prime.

It is a super-2 number, since 2×208139497² = 86644100422826018, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (208139297) 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, 104069748 + 104069749.

It is an arithmetic number, because the mean of its divisors is an integer number (104069749).

Almost surely, 2^208139497 is an apocalyptic number.

It is an amenable number.

208139497 is a deficient number, since it is larger than the sum of its proper divisors (1).

208139497 is an equidigital number, since it uses as much as digits as its factorization.

208139497 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 208139497 is about 14427.0404795994. The cubic root of 208139497 is about 592.6316389902.

The spelling of 208139497 in words is "two hundred eight million, one hundred thirty-nine thousand, four hundred ninety-seven".