21210130891 has 2 divisors, whose sum is σ = 21210130892. Its totient is φ = 21210130890.

The previous prime is 21210130873. The next prime is 21210130927. The reversal of 21210130891 is 19803101212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21210130891 - 2⁵ = 21210130859 is a prime.

It is not a weakly prime, because it can be changed into another prime (21210130811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605065445 + 10605065446.

It is an arithmetic number, because the mean of its divisors is an integer number (10605065446).

Almost surely, 2^21210130891 is an apocalyptic number.

21210130891 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210130891 is an equidigital number, since it uses as much as digits as its factorization.

21210130891 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 28.

The spelling of 21210130891 in words is "twenty-one billion, two hundred ten million, one hundred thirty thousand, eight hundred ninety-one".