21839005691 has 2 divisors, whose sum is σ = 21839005692. Its totient is φ = 21839005690.

The previous prime is 21839005633. The next prime is 21839005717. The reversal of 21839005691 is 19650093812.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21839005691 - 2²² = 21834811387 is a prime.

It is not a weakly prime, because it can be changed into another prime (21839005621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10919502845 + 10919502846.

It is an arithmetic number, because the mean of its divisors is an integer number (10919502846).

Almost surely, 2^21839005691 is an apocalyptic number.

21839005691 is a deficient number, since it is larger than the sum of its proper divisors (1).

21839005691 is an equidigital number, since it uses as much as digits as its factorization.

21839005691 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 44.

The spelling of 21839005691 in words is "twenty-one billion, eight hundred thirty-nine million, five thousand, six hundred ninety-one".