1291326623 has 4 divisors (see below), whose sum is σ = 1292328168. Its totient is φ = 1290325080.

The previous prime is 1291326601. The next prime is 1291326661. The reversal of 1291326623 is 3266231921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3266231921 = 14207 ⋅229903.

It is a cyclic number.

It is not a de Polignac number, because 1291326623 - 2¹⁶ = 1291261087 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1291320623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 498836 + ... + 501417.

It is an arithmetic number, because the mean of its divisors is an integer number (323082042).

Almost surely, 2^1291326623 is an apocalyptic number.

1291326623 is a deficient number, since it is larger than the sum of its proper divisors (1001545).

1291326623 is a wasteful number, since it uses less digits than its factorization.

1291326623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1001544.

The product of its digits is 23328, while the sum is 35.

The square root of 1291326623 is about 35935.0333657839. The cubic root of 1291326623 is about 1088.9602696535.

The spelling of 1291326623 in words is "one billion, two hundred ninety-one million, three hundred twenty-six thousand, six hundred twenty-three".