21609830591 has 2 divisors, whose sum is σ = 21609830592. Its totient is φ = 21609830590.

The previous prime is 21609830521. The next prime is 21609830597. The reversal of 21609830591 is 19503890612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21609830591 - 2¹⁰ = 21609829567 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21609830597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10804915295 + 10804915296.

It is an arithmetic number, because the mean of its divisors is an integer number (10804915296).

Almost surely, 2^21609830591 is an apocalyptic number.

21609830591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21609830591 is an equidigital number, since it uses as much as digits as its factorization.

21609830591 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 21609830591 in words is "twenty-one billion, six hundred nine million, eight hundred thirty thousand, five hundred ninety-one".