1206435561 has 4 divisors (see below), whose sum is σ = 1608580752. Its totient is φ = 804290372.

The previous prime is 1206435553. The next prime is 1206435569. The reversal of 1206435561 is 1655346021.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (1206435553) and next prime (1206435569).

It is a cyclic number.

It is not a de Polignac number, because 1206435561 - 2³ = 1206435553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1206435569) 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 in 3 ways as a sum of consecutive naturals, for example, 201072591 + ... + 201072596.

It is an arithmetic number, because the mean of its divisors is an integer number (402145188).

Almost surely, 2^1206435561 is an apocalyptic number.

It is an amenable number.

1206435561 is a deficient number, since it is larger than the sum of its proper divisors (402145191).

1206435561 is an equidigital number, since it uses as much as digits as its factorization.

1206435561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402145190.

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 1206435561 is about 34733.7812655058. The cubic root of 1206435561 is about 1064.5548511024.

The spelling of 1206435561 in words is "one billion, two hundred six million, four hundred thirty-five thousand, five hundred sixty-one".