20991373411 has 2 divisors, whose sum is σ = 20991373412. Its totient is φ = 20991373410.

The previous prime is 20991373409. The next prime is 20991373457. The reversal of 20991373411 is 11437319902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20991373411 - 2¹ = 20991373409 is a prime.

Together with 20991373409, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20991373111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10495686705 + 10495686706.

It is an arithmetic number, because the mean of its divisors is an integer number (10495686706).

Almost surely, 2^20991373411 is an apocalyptic number.

20991373411 is a deficient number, since it is larger than the sum of its proper divisors (1).

20991373411 is an equidigital number, since it uses as much as digits as its factorization.

20991373411 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 40.

The spelling of 20991373411 in words is "twenty billion, nine hundred ninety-one million, three hundred seventy-three thousand, four hundred eleven".