1261815842 has 16 divisors (see below), whose sum is σ = 2179628352. Its totient is φ = 536649360.

The previous prime is 1261815827. The next prime is 1261815851. The reversal of 1261815842 is 2485181621.

It is a junction number, because it is equal to n+sod(n) for n = 1261815796 and 1261815805.

It is an unprimeable number.

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, 342173 + ... + 345840.

It is an arithmetic number, because the mean of its divisors is an integer number (136226772).

Almost surely, 2^1261815842 is an apocalyptic number.

1261815842 is a deficient number, since it is larger than the sum of its proper divisors (917812510).

1261815842 is a wasteful number, since it uses less digits than its factorization.

1261815842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688153.

The product of its digits is 30720, while the sum is 38.

The square root of 1261815842 is about 35522.0472664513. The cubic root of 1261815842 is about 1080.6009007425.

The spelling of 1261815842 in words is "one billion, two hundred sixty-one million, eight hundred fifteen thousand, eight hundred forty-two".