1268997591 has 4 divisors (see below), whose sum is σ = 1691996792. Its totient is φ = 845998392.

The previous prime is 1268997563. The next prime is 1268997629. The reversal of 1268997591 is 1957998621.

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

It is not a de Polignac number, because 1268997591 - 2⁷ = 1268997463 is a prime.

It is a super-2 number, since 2×1268997591² = 3220709771927606562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1268993591) 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 3 ways as a sum of consecutive naturals, for example, 211499596 + ... + 211499601.

It is an arithmetic number, because the mean of its divisors is an integer number (422999198).

Almost surely, 2^1268997591 is an apocalyptic number.

1268997591 is a deficient number, since it is larger than the sum of its proper divisors (422999201).

1268997591 is an equidigital number, since it uses as much as digits as its factorization.

1268997591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422999200.

The product of its digits is 2449440, while the sum is 57.

The square root of 1268997591 is about 35622.9924486981. The cubic root of 1268997591 is about 1082.6471389614.

The spelling of 1268997591 in words is "one billion, two hundred sixty-eight million, nine hundred ninety-seven thousand, five hundred ninety-one".