1991266707 has 16 divisors (see below), whose sum is σ = 2665175040. Its totient is φ = 1322446272.

The previous prime is 1991266649. The next prime is 1991266723. The reversal of 1991266707 is 7076621991.

It is a happy number.

It is not a de Polignac number, because 1991266707 - 2¹⁹ = 1990742419 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1991266727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1388863 + ... + 1390295.

It is an arithmetic number, because the mean of its divisors is an integer number (166573440).

Almost surely, 2^1991266707 is an apocalyptic number.

1991266707 is a deficient number, since it is larger than the sum of its proper divisors (673908333).

1991266707 is a wasteful number, since it uses less digits than its factorization.

1991266707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2882.

The product of its (nonzero) digits is 285768, while the sum is 48.

The square root of 1991266707 is about 44623.6115414250. The cubic root of 1991266707 is about 1258.0844974892.

The spelling of 1991266707 in words is "one billion, nine hundred ninety-one million, two hundred sixty-six thousand, seven hundred seven".