20910909291 has 12 divisors (see below), whose sum is σ = 28809623016. Its totient is φ = 13490907360.

The previous prime is 20910909289. The next prime is 20910909301. The reversal of 20910909291 is 19290901902.

It is not a de Polignac number, because 20910909291 - 2¹ = 20910909289 is a prime.

It is a super-2 number, since 2×20910909291² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20910909491) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3623706 + ... + 3629471.

It is an arithmetic number, because the mean of its divisors is an integer number (2400801918).

Almost surely, 2^20910909291 is an apocalyptic number.

20910909291 is a deficient number, since it is larger than the sum of its proper divisors (7898713725).

20910909291 is an equidigital number, since it uses as much as digits as its factorization.

20910909291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7253242 (or 7253211 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 42.

The spelling of 20910909291 in words is "twenty billion, nine hundred ten million, nine hundred nine thousand, two hundred ninety-one".