21213009999997 has 2 divisors, whose sum is σ = 21213009999998. Its totient is φ = 21213009999996.

The previous prime is 21213009999953. The next prime is 21213010000009. The reversal of 21213009999997 is 79999990031212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16063895664441 + 5149114335556 = 4007979^2 + 2269166^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213009999997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21213009999947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606504999998 + 10606504999999.

It is an arithmetic number, because the mean of its divisors is an integer number (10606504999999).

Almost surely, 2^{21213009999997} is an apocalyptic number.

It is an amenable number.

21213009999997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213009999997 is an equidigital number, since it uses as much as digits as its factorization.

21213009999997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 44641044, while the sum is 70.

The spelling of 21213009999997 in words is "twenty-one trillion, two hundred thirteen billion, nine million, nine hundred ninety-nine thousand, nine hundred ninety-seven".