1261665627 has 16 divisors (see below), whose sum is σ = 1732449792. Its totient is φ = 816121440.

The previous prime is 1261665611. The next prime is 1261665637. The reversal of 1261665627 is 7265661621.

It is not a de Polignac number, because 1261665627 - 2⁴ = 1261665611 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1261665637) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 25252 + ... + 56222.

It is an arithmetic number, because the mean of its divisors is an integer number (108278112).

Almost surely, 2^1261665627 is an apocalyptic number.

1261665627 is a deficient number, since it is larger than the sum of its proper divisors (470784165).

1261665627 is a wasteful number, since it uses less digits than its factorization.

1261665627 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31378.

The product of its digits is 181440, while the sum is 42.

The square root of 1261665627 is about 35519.9328124365. The cubic root of 1261665627 is about 1080.5580183872.

The spelling of 1261665627 in words is "one billion, two hundred sixty-one million, six hundred sixty-five thousand, six hundred twenty-seven".