1261365986 has 8 divisors (see below), whose sum is σ = 1920288720. Its totient is φ = 621269748.

The previous prime is 1261365979. The next prime is 1261365997. The reversal of 1261365986 is 6895631621.

It is a happy number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1261365986.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4706456 + ... + 4706723.

It is an arithmetic number, because the mean of its divisors is an integer number (240036090).

Almost surely, 2^1261365986 is an apocalyptic number.

1261365986 is a deficient number, since it is larger than the sum of its proper divisors (658922734).

1261365986 is an equidigital number, since it uses as much as digits as its factorization.

1261365986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9413248.

The product of its digits is 466560, while the sum is 47.

The square root of 1261365986 is about 35515.7146345107. The cubic root of 1261365986 is about 1080.4724687471.

The spelling of 1261365986 in words is "one billion, two hundred sixty-one million, three hundred sixty-five thousand, nine hundred eighty-six".