1213649791 has 4 divisors (see below), whose sum is σ = 1215118152. Its totient is φ = 1212181432.

The previous prime is 1213649779. The next prime is 1213649807. The reversal of 1213649791 is 1979463121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1979463121 = 29 ⋅68257349.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1213649791 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 (1213649191) 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, 732940 + ... + 734593.

It is an arithmetic number, because the mean of its divisors is an integer number (303779538).

Almost surely, 2^1213649791 is an apocalyptic number.

1213649791 is a deficient number, since it is larger than the sum of its proper divisors (1468361).

1213649791 is an equidigital number, since it uses as much as digits as its factorization.

1213649791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1468360.

The product of its digits is 81648, while the sum is 43.

The square root of 1213649791 is about 34837.4768173586. The cubic root of 1213649791 is about 1066.6725732854.

The spelling of 1213649791 in words is "one billion, two hundred thirteen million, six hundred forty-nine thousand, seven hundred ninety-one".