1290426691 has 2 divisors, whose sum is σ = 1290426692. Its totient is φ = 1290426690.

The previous prime is 1290426671. The next prime is 1290426703. The reversal of 1290426691 is 1966240921.

It is a strong prime.

It is an emirp because it is prime and its reverse (1966240921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1290426691 - 2¹⁷ = 1290295619 is a prime.

It is a super-3 number, since 3×1290426691³ (a number of 28 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (1290426611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645213345 + 645213346.

It is an arithmetic number, because the mean of its divisors is an integer number (645213346).

Almost surely, 2^1290426691 is an apocalyptic number.

1290426691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1290426691 is an equidigital number, since it uses as much as digits as its factorization.

1290426691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 1290426691 is about 35922.5095309334. The cubic root of 1290426691 is about 1088.7072435748.

Subtracting 1290426691 from its reverse (1966240921), we obtain a triangular number (675814230 = T₃₆₇₆₄).

The spelling of 1290426691 in words is "one billion, two hundred ninety million, four hundred twenty-six thousand, six hundred ninety-one".