1291973251 has 4 divisors (see below), whose sum is σ = 1294152552. Its totient is φ = 1289793952.

The previous prime is 1291973233. The next prime is 1291973279. The reversal of 1291973251 is 1523791921.

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

It is a cyclic number.

It is not a de Polignac number, because 1291973251 - 2⁵ = 1291973219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291973281) 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 3 ways as a sum of consecutive naturals, for example, 1088761 + ... + 1089946.

It is an arithmetic number, because the mean of its divisors is an integer number (323538138).

Almost surely, 2^1291973251 is an apocalyptic number.

1291973251 is a deficient number, since it is larger than the sum of its proper divisors (2179301).

1291973251 is an equidigital number, since it uses as much as digits as its factorization.

1291973251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2179300.

The product of its digits is 34020, while the sum is 40.

The square root of 1291973251 is about 35944.0294207536. The cubic root of 1291973251 is about 1089.1420038709.

The spelling of 1291973251 in words is "one billion, two hundred ninety-one million, nine hundred seventy-three thousand, two hundred fifty-one".