206191745 has 8 divisors (see below), whose sum is σ = 247837416. Its totient is φ = 164681856.

The previous prime is 206191717. The next prime is 206191771. The reversal of 206191745 is 547191602.

It can be written as a sum of positive squares in 4 ways, for example, as 13315201 + 192876544 = 3649^2 + 13888^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 206191745 - 2¹⁸ = 205929601 is a prime.

It is a super-2 number, since 2×206191745² = 85030071412290050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 30572 + ... + 36701.

It is an arithmetic number, because the mean of its divisors is an integer number (30979677).

Almost surely, 2^206191745 is an apocalyptic number.

It is an amenable number.

206191745 is a deficient number, since it is larger than the sum of its proper divisors (41645671).

206191745 is an equidigital number, since it uses as much as digits as its factorization.

206191745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67891.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 206191745 is about 14359.3782943413. The cubic root of 206191745 is about 590.7772433789. Note that the first 3 decimals are identical.

The spelling of 206191745 in words is "two hundred six million, one hundred ninety-one thousand, seven hundred forty-five".