1261791 has 16 divisors (see below), whose sum is σ = 1980000. Its totient is φ = 791424.

The previous prime is 1261789. The next prime is 1261801. The reversal of 1261791 is 1971621.

It is not a de Polignac number, because 1261791 - 2¹ = 1261789 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 916 + ... + 1833.

It is an arithmetic number, because the mean of its divisors is an integer number (123750).

2^1261791 is an apocalyptic number.

1261791 is a deficient number, since it is larger than the sum of its proper divisors (718209).

1261791 is a wasteful number, since it uses less digits than its factorization.

1261791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2775 (or 2769 counting only the distinct ones).

The product of its digits is 756, while the sum is 27.

The square root of 1261791 is about 1123.2947075456. The cubic root of 1261791 is about 108.0593809252.

The spelling of 1261791 in words is "one million, two hundred sixty-one thousand, seven hundred ninety-one".