1266440638 has 8 divisors (see below), whose sum is σ = 1908180288. Its totient is φ = 630380544.

The previous prime is 1266440627. The next prime is 1266440641. The reversal of 1266440638 is 8360446621.

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 1266440638.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1419331 + ... + 1420222.

It is an arithmetic number, because the mean of its divisors is an integer number (238522536).

Almost surely, 2^1266440638 is an apocalyptic number.

1266440638 is a deficient number, since it is larger than the sum of its proper divisors (641739650).

1266440638 is a wasteful number, since it uses less digits than its factorization.

1266440638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2839778.

The product of its (nonzero) digits is 165888, while the sum is 40.

The square root of 1266440638 is about 35587.0852697998. The cubic root of 1266440638 is about 1081.9194939663.

The spelling of 1266440638 in words is "one billion, two hundred sixty-six million, four hundred forty thousand, six hundred thirty-eight".