1291145389 has 2 divisors, whose sum is σ = 1291145390. Its totient is φ = 1291145388.

The previous prime is 1291145371. The next prime is 1291145419. The reversal of 1291145389 is 9835411921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1238336100 + 52809289 = 35190^2 + 7267^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291145389 - 2⁵ = 1291145357 is a prime.

It is a super-2 number, since 2×1291145389² = 3334112831071922642, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291145689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645572694 + 645572695.

It is an arithmetic number, because the mean of its divisors is an integer number (645572695).

Almost surely, 2^1291145389 is an apocalyptic number.

It is an amenable number.

1291145389 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291145389 is an equidigital number, since it uses as much as digits as its factorization.

1291145389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 43.

The square root of 1291145389 is about 35932.5115876973. The cubic root of 1291145389 is about 1088.9093231164.

The spelling of 1291145389 in words is "one billion, two hundred ninety-one million, one hundred forty-five thousand, three hundred eighty-nine".