1291079691 has 48 divisors (see below), whose sum is σ = 2088882432. Its totient is φ = 761812800.

The previous prime is 1291079663. The next prime is 1291079693. The reversal of 1291079691 is 1969701921.

It is not a de Polignac number, because 1291079691 - 2¹¹ = 1291077643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1291079693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 582301 + ... + 584513.

It is an arithmetic number, because the mean of its divisors is an integer number (43518384).

Almost surely, 2^1291079691 is an apocalyptic number.

1291079691 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1291079691 is a deficient number, since it is larger than the sum of its proper divisors (797802741).

1291079691 is a wasteful number, since it uses less digits than its factorization.

1291079691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2384 (or 2381 counting only the distinct ones).

The product of its (nonzero) digits is 61236, while the sum is 45.

The square root of 1291079691 is about 35931.5973900410. The cubic root of 1291079691 is about 1088.8908536296.

The spelling of 1291079691 in words is "one billion, two hundred ninety-one million, seventy-nine thousand, six hundred ninety-one".