20011001211997 has 4 divisors (see below), whose sum is σ = 20011083303420. Its totient is φ = 20010919120576.

The previous prime is 20011001211973. The next prime is 20011001212009. The reversal of 20011001211997 is 79911210011002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14005041313561 + 6005959898436 = 3742331^2 + 2450706^2 .

It is a cyclic number.

It is not a de Polignac number, because 20011001211997 - 2⁴³ = 11214908189789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20011001241997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40678972 + ... + 41167957.

It is an arithmetic number, because the mean of its divisors is an integer number (5002770825855).

Almost surely, 2^{20011001211997} is an apocalyptic number.

It is an amenable number.

20011001211997 is a deficient number, since it is larger than the sum of its proper divisors (82091423).

20011001211997 is an equidigital number, since it uses as much as digits as its factorization.

20011001211997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82091422.

The product of its (nonzero) digits is 2268, while the sum is 34.

Adding to 20011001211997 its reverse (79911210011002), we get a palindrome (99922211222999).

The spelling of 20011001211997 in words is "twenty trillion, eleven billion, one million, two hundred eleven thousand, nine hundred ninety-seven".