21204130291 has 2 divisors, whose sum is σ = 21204130292. Its totient is φ = 21204130290.

The previous prime is 21204130289. The next prime is 21204130369. The reversal of 21204130291 is 19203140212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21204130291 - 2¹ = 21204130289 is a prime.

Together with 21204130289, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21204134291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602065145 + 10602065146.

It is an arithmetic number, because the mean of its divisors is an integer number (10602065146).

Almost surely, 2^21204130291 is an apocalyptic number.

21204130291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204130291 is an equidigital number, since it uses as much as digits as its factorization.

21204130291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 25.

The spelling of 21204130291 in words is "twenty-one billion, two hundred four million, one hundred thirty thousand, two hundred ninety-one".