21011012291 has 2 divisors, whose sum is σ = 21011012292. Its totient is φ = 21011012290.

The previous prime is 21011012273. The next prime is 21011012311. The reversal of 21011012291 is 19221011012.

It is an a-pointer prime, because the next prime (21011012311) can be obtained adding 21011012291 to its sum of digits (20).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21011012291 is a prime.

It is not a weakly prime, because it can be changed into another prime (21011012791) 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, 10505506145 + 10505506146.

It is an arithmetic number, because the mean of its divisors is an integer number (10505506146).

Almost surely, 2^21011012291 is an apocalyptic number.

21011012291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011012291 is an equidigital number, since it uses as much as digits as its factorization.

21011012291 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 21011012291 in words is "twenty-one billion, eleven million, twelve thousand, two hundred ninety-one".