78454822421 has 2 divisors, whose sum is σ = 78454822422. Its totient is φ = 78454822420.

The previous prime is 78454822349. The next prime is 78454822423. The reversal of 78454822421 is 12422845487.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60954178321 + 17500644100 = 246889^2 + 132290^2 .

It is a cyclic number.

It is not a de Polignac number, because 78454822421 - 2¹⁴ = 78454806037 is a prime.

It is a super-2 number, since 2×78454822421² (a number of 23 digits) contains 22 as substring.

Together with 78454822423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78454822423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39227411210 + 39227411211.

It is an arithmetic number, because the mean of its divisors is an integer number (39227411211).

Almost surely, 2^78454822421 is an apocalyptic number.

It is an amenable number.

78454822421 is a deficient number, since it is larger than the sum of its proper divisors (1).

78454822421 is an equidigital number, since it uses as much as digits as its factorization.

78454822421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1146880, while the sum is 47.

The spelling of 78454822421 in words is "seventy-eight billion, four hundred fifty-four million, eight hundred twenty-two thousand, four hundred twenty-one".