21434020591 has 2 divisors, whose sum is σ = 21434020592. Its totient is φ = 21434020590.

The previous prime is 21434020583. The next prime is 21434020609. The reversal of 21434020591 is 19502043412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21434020591 - 2³ = 21434020583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21434020691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10717010295 + 10717010296.

It is an arithmetic number, because the mean of its divisors is an integer number (10717010296).

Almost surely, 2^21434020591 is an apocalyptic number.

21434020591 is a deficient number, since it is larger than the sum of its proper divisors (1).

21434020591 is an equidigital number, since it uses as much as digits as its factorization.

21434020591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 31.

The spelling of 21434020591 in words is "twenty-one billion, four hundred thirty-four million, twenty thousand, five hundred ninety-one".