1291538477 has 2 divisors, whose sum is σ = 1291538478. Its totient is φ = 1291538476.

The previous prime is 1291538419. The next prime is 1291538483. The reversal of 1291538477 is 7748351921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 912885796 + 378652681 = 30214^2 + 19459^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291538477 - 2¹² = 1291534381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291238477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645769238 + 645769239.

It is an arithmetic number, because the mean of its divisors is an integer number (645769239).

Almost surely, 2^1291538477 is an apocalyptic number.

It is an amenable number.

1291538477 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291538477 is an equidigital number, since it uses as much as digits as its factorization.

1291538477 is an evil number, because the sum of its binary digits is even.

The product of its digits is 423360, while the sum is 47.

The square root of 1291538477 is about 35937.9809811291. The cubic root of 1291538477 is about 1089.0198177104.

The spelling of 1291538477 in words is "one billion, two hundred ninety-one million, five hundred thirty-eight thousand, four hundred seventy-seven".