1291478477 has 2 divisors, whose sum is σ = 1291478478. Its totient is φ = 1291478476.

The previous prime is 1291478473. The next prime is 1291478479. The reversal of 1291478477 is 7748741921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1270993801 + 20484676 = 35651^2 + 4526^2 .

It is an emirp because it is prime and its reverse (7748741921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291478477 - 2² = 1291478473 is a prime.

Together with 1291478479, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291478471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645739238 + 645739239.

It is an arithmetic number, because the mean of its divisors is an integer number (645739239).

Almost surely, 2^1291478477 is an apocalyptic number.

It is an amenable number.

1291478477 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291478477 is an equidigital number, since it uses as much as digits as its factorization.

1291478477 is an evil number, because the sum of its binary digits is even.

The product of its digits is 790272, while the sum is 50.

The square root of 1291478477 is about 35937.1461999976. The cubic root of 1291478477 is about 1089.0029535333.

The spelling of 1291478477 in words is "one billion, two hundred ninety-one million, four hundred seventy-eight thousand, four hundred seventy-seven".