1209780561 has 8 divisors (see below), whose sum is σ = 1759680864. Its totient is φ = 733200320.

The previous prime is 1209780553. The next prime is 1209780581. The reversal of 1209780561 is 1650879021.

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 1209780561 - 2³ = 1209780553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1209780581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18329976 + ... + 18330041.

It is an arithmetic number, because the mean of its divisors is an integer number (219960108).

Almost surely, 2^1209780561 is an apocalyptic number.

1209780561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1209780561 is a deficient number, since it is larger than the sum of its proper divisors (549900303).

1209780561 is a wasteful number, since it uses less digits than its factorization.

1209780561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36660031.

The product of its (nonzero) digits is 30240, while the sum is 39.

The square root of 1209780561 is about 34781.8999049793. The cubic root of 1209780561 is about 1065.5378156023.

The spelling of 1209780561 in words is "one billion, two hundred nine million, seven hundred eighty thousand, five hundred sixty-one".