1561242766 has 8 divisors (see below), whose sum is σ = 2352091320. Its totient is φ = 777212328.

The previous prime is 1561242733. The next prime is 1561242769. The reversal of 1561242766 is 6672421651.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561242769) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1703956 + ... + 1704871.

It is an arithmetic number, because the mean of its divisors is an integer number (294011415).

Almost surely, 2^1561242766 is an apocalyptic number.

1561242766 is a deficient number, since it is larger than the sum of its proper divisors (790848554).

1561242766 is a wasteful number, since it uses less digits than its factorization.

1561242766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3409058.

The product of its digits is 120960, while the sum is 40.

The square root of 1561242766 is about 39512.5646598648. The cubic root of 1561242766 is about 1160.0858948484.

The spelling of 1561242766 in words is "one billion, five hundred sixty-one million, two hundred forty-two thousand, seven hundred sixty-six".