21220101111997 has 2 divisors, whose sum is σ = 21220101111998. Its totient is φ = 21220101111996.

The previous prime is 21220101111991. The next prime is 21220101112051. The reversal of 21220101111997 is 79911110102212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18766275984036 + 2453825127961 = 4332006^2 + 1566469^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220101111997 - 2¹⁹ = 21220100587709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21220101111991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610050555998 + 10610050555999.

It is an arithmetic number, because the mean of its divisors is an integer number (10610050555999).

Almost surely, 2^{21220101111997} is an apocalyptic number.

It is an amenable number.

21220101111997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220101111997 is an equidigital number, since it uses as much as digits as its factorization.

21220101111997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 37.

The spelling of 21220101111997 in words is "twenty-one trillion, two hundred twenty billion, one hundred one million, one hundred eleven thousand, nine hundred ninety-seven".