21212220010997 has 2 divisors, whose sum is σ = 21212220010998. Its totient is φ = 21212220010996.

The previous prime is 21212220010973. The next prime is 21212220011083. The reversal of 21212220010997 is 79901002221212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21118491576196 + 93728434801 = 4595486^2 + 306151^2 .

It is a cyclic number.

It is not a de Polignac number, because 21212220010997 - 2¹⁴ = 21212219994613 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21212220010997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21212220013997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606110005498 + 10606110005499.

It is an arithmetic number, because the mean of its divisors is an integer number (10606110005499).

Almost surely, 2^{21212220010997} is an apocalyptic number.

It is an amenable number.

21212220010997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21212220010997 is an equidigital number, since it uses as much as digits as its factorization.

21212220010997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 38.

The spelling of 21212220010997 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty million, ten thousand, nine hundred ninety-seven".