21354321240397 has 2 divisors, whose sum is σ = 21354321240398. Its totient is φ = 21354321240396.

The previous prime is 21354321240377. The next prime is 21354321240493. The reversal of 21354321240397 is 79304212345312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17843367187881 + 3510954052516 = 4224141^2 + 1873754^2 .

It is a cyclic number.

It is not a de Polignac number, because 21354321240397 - 2¹⁵ = 21354321207629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21354321240377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10677160620198 + 10677160620199.

It is an arithmetic number, because the mean of its divisors is an integer number (10677160620199).

Almost surely, 2^{21354321240397} is an apocalyptic number.

It is an amenable number.

21354321240397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21354321240397 is an equidigital number, since it uses as much as digits as its factorization.

21354321240397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1088640, while the sum is 46.

The spelling of 21354321240397 in words is "twenty-one trillion, three hundred fifty-four billion, three hundred twenty-one million, two hundred forty thousand, three hundred ninety-seven".