1291997393 has 4 divisors (see below), whose sum is σ = 1322043888. Its totient is φ = 1261950900.

The previous prime is 1291997387. The next prime is 1291997401. The reversal of 1291997393 is 3937991921.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1291997393 - 2¹⁶ = 1291931857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291997593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15023183 + ... + 15023268.

It is an arithmetic number, because the mean of its divisors is an integer number (330510972).

Almost surely, 2^1291997393 is an apocalyptic number.

It is an amenable number.

1291997393 is a deficient number, since it is larger than the sum of its proper divisors (30046495).

1291997393 is an equidigital number, since it uses as much as digits as its factorization.

1291997393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30046494.

The product of its digits is 826686, while the sum is 53.

The square root of 1291997393 is about 35944.3652468645. The cubic root of 1291997393 is about 1089.1487877839.

The spelling of 1291997393 in words is "one billion, two hundred ninety-one million, nine hundred ninety-seven thousand, three hundred ninety-three".