78213023331221 has 2 divisors, whose sum is σ = 78213023331222. Its totient is φ = 78213023331220.

The previous prime is 78213023331139. The next prime is 78213023331227. The reversal of 78213023331221 is 12213332031287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62686980435121 + 15526042896100 = 7917511^2 + 3940310^2 .

It is an emirp because it is prime and its reverse (12213332031287) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78213023331221 is a prime.

It is a super-2 number, since 2×78213023331221² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78213023331227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39106511665610 + 39106511665611.

It is an arithmetic number, because the mean of its divisors is an integer number (39106511665611).

Almost surely, 2^{78213023331221} is an apocalyptic number.

It is an amenable number.

78213023331221 is a deficient number, since it is larger than the sum of its proper divisors (1).

78213023331221 is an equidigital number, since it uses as much as digits as its factorization.

78213023331221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 38.

The spelling of 78213023331221 in words is "seventy-eight trillion, two hundred thirteen billion, twenty-three million, three hundred thirty-one thousand, two hundred twenty-one".