1242728561 has 8 divisors (see below), whose sum is σ = 1290132480. Its totient is φ = 1195628112.

The previous prime is 1242728537. The next prime is 1242728569. The reversal of 1242728561 is 1658272421.

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 1242728561 - 2²² = 1238534257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1242728569) by changing a digit.

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, 67505 + ... + 83918.

It is an arithmetic number, because the mean of its divisors is an integer number (161266560).

Almost surely, 2^1242728561 is an apocalyptic number.

It is an amenable number.

1242728561 is a deficient number, since it is larger than the sum of its proper divisors (47403919).

1242728561 is a wasteful number, since it uses less digits than its factorization.

1242728561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151735.

The product of its digits is 53760, while the sum is 38.

The square root of 1242728561 is about 35252.3553964838. The cubic root of 1242728561 is about 1075.1245029046.

The spelling of 1242728561 in words is "one billion, two hundred forty-two million, seven hundred twenty-eight thousand, five hundred sixty-one".