21010312091 has 2 divisors, whose sum is σ = 21010312092. Its totient is φ = 21010312090.

The previous prime is 21010312073. The next prime is 21010312133. The reversal of 21010312091 is 19021301012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21010312091 - 2¹⁴ = 21010295707 is a prime.

It is a super-2 number, since 2×21010312091² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21010312061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505156045 + 10505156046.

It is an arithmetic number, because the mean of its divisors is an integer number (10505156046).

Almost surely, 2^21010312091 is an apocalyptic number.

21010312091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010312091 is an equidigital number, since it uses as much as digits as its factorization.

21010312091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 20.

The spelling of 21010312091 in words is "twenty-one billion, ten million, three hundred twelve thousand, ninety-one".