1340566561 has 4 divisors (see below), whose sum is σ = 1362543124. Its totient is φ = 1318590000.

The previous prime is 1340566547. The next prime is 1340566583. The reversal of 1340566561 is 1656650431.

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 354606561 + 985960000 = 18831^2 + 31400^2 .

It is a cyclic number.

It is not a de Polignac number, because 1340566561 - 2⁵ = 1340566529 is a prime.

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 1340566561.

It is not an unprimeable number, because it can be changed into a prime (1340566541) 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 in 3 ways as a sum of consecutive naturals, for example, 10988190 + ... + 10988311.

It is an arithmetic number, because the mean of its divisors is an integer number (340635781).

Almost surely, 2^1340566561 is an apocalyptic number.

It is an amenable number.

1340566561 is a deficient number, since it is larger than the sum of its proper divisors (21976563).

1340566561 is an equidigital number, since it uses as much as digits as its factorization.

1340566561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21976562.

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 1340566561 is about 36613.7482511693. The cubic root of 1340566561 is about 1102.6291273284.

The spelling of 1340566561 in words is "one billion, three hundred forty million, five hundred sixty-six thousand, five hundred sixty-one".