1242255661 has 4 divisors (see below), whose sum is σ = 1254555324. Its totient is φ = 1229956000.

The previous prime is 1242255659. The next prime is 1242255683. The reversal of 1242255661 is 1665522421.

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 883872900 + 358382761 = 29730^2 + 18931^2 .

It is a cyclic number.

It is not a de Polignac number, because 1242255661 - 2¹ = 1242255659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1242255631) 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 3 ways as a sum of consecutive naturals, for example, 6149680 + ... + 6149881.

It is an arithmetic number, because the mean of its divisors is an integer number (313638831).

Almost surely, 2^1242255661 is an apocalyptic number.

It is an amenable number.

1242255661 is a deficient number, since it is larger than the sum of its proper divisors (12299663).

1242255661 is a wasteful number, since it uses less digits than its factorization.

1242255661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12299662.

The product of its digits is 28800, while the sum is 34.

The square root of 1242255661 is about 35245.6474050343. The cubic root of 1242255661 is about 1074.9881119291.

The spelling of 1242255661 in words is "one billion, two hundred forty-two million, two hundred fifty-five thousand, six hundred sixty-one".