1291185541 has 2 divisors, whose sum is σ = 1291185542. Its totient is φ = 1291185540.

The previous prime is 1291185521. The next prime is 1291185583. The reversal of 1291185541 is 1455811921.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1039804516 + 251381025 = 32246^2 + 15855^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291185541 - 2⁵ = 1291185509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1291185541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291185521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645592770 + 645592771.

It is an arithmetic number, because the mean of its divisors is an integer number (645592771).

Almost surely, 2^1291185541 is an apocalyptic number.

It is an amenable number.

1291185541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291185541 is an equidigital number, since it uses as much as digits as its factorization.

1291185541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 37.

The square root of 1291185541 is about 35933.0702974294. The cubic root of 1291185541 is about 1088.9206106224.

The spelling of 1291185541 in words is "one billion, two hundred ninety-one million, one hundred eighty-five thousand, five hundred forty-one".