20991813341 has 2 divisors, whose sum is σ = 20991813342. Its totient is φ = 20991813340.

The previous prime is 20991813313. The next prime is 20991813439. The reversal of 20991813341 is 14331819902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13603723225 + 7388090116 = 116635^2 + 85954^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20991813341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20991813641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10495906670 + 10495906671.

It is an arithmetic number, because the mean of its divisors is an integer number (10495906671).

Almost surely, 2^20991813341 is an apocalyptic number.

It is an amenable number.

20991813341 is a deficient number, since it is larger than the sum of its proper divisors (1).

20991813341 is an equidigital number, since it uses as much as digits as its factorization.

20991813341 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 41.

The spelling of 20991813341 in words is "twenty billion, nine hundred ninety-one million, eight hundred thirteen thousand, three hundred forty-one".