1266630391 has 4 divisors (see below), whose sum is σ = 1364063512. Its totient is φ = 1169197272.

The previous prime is 1266630389. The next prime is 1266630427. The reversal of 1266630391 is 1930366621.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1266630391 - 2¹ = 1266630389 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1266630391.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266630301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48716541 + ... + 48716566.

It is an arithmetic number, because the mean of its divisors is an integer number (341015878).

Almost surely, 2^1266630391 is an apocalyptic number.

1266630391 is a deficient number, since it is larger than the sum of its proper divisors (97433121).

1266630391 is an equidigital number, since it uses as much as digits as its factorization.

1266630391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97433120.

The product of its (nonzero) digits is 34992, while the sum is 37.

The square root of 1266630391 is about 35589.7512073350. The cubic root of 1266630391 is about 1081.9735265599.

The spelling of 1266630391 in words is "one billion, two hundred sixty-six million, six hundred thirty thousand, three hundred ninety-one".