206426203561 has 4 divisors (see below), whose sum is σ = 206429165572. Its totient is φ = 206423241552.

The previous prime is 206426203523. The next prime is 206426203631. The reversal of 206426203561 is 165302624602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 133279755625 + 73146447936 = 365075^2 + 270456^2 .

It is a cyclic number.

It is not a de Polignac number, because 206426203561 - 2²¹ = 206424106409 is a prime.

It is a super-2 number, since 2×206426203561² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 206426203561.

It is not an unprimeable number, because it can be changed into a prime (206426204561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1373886 + ... + 1516711.

It is an arithmetic number, because the mean of its divisors is an integer number (51607291393).

Almost surely, 2^206426203561 is an apocalyptic number.

It is an amenable number.

206426203561 is a deficient number, since it is larger than the sum of its proper divisors (2962011).

206426203561 is an equidigital number, since it uses as much as digits as its factorization.

206426203561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2962010.

The product of its (nonzero) digits is 103680, while the sum is 37.

The spelling of 206426203561 in words is "two hundred six billion, four hundred twenty-six million, two hundred three thousand, five hundred sixty-one".